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Revision 1.58 by root, Sun May 1 17:19:39 2016 UTC vs.
Revision 1.62 by root, Sat Aug 25 19:59:18 2018 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 $nfd = IO::AIO::get_fdlimit [EXPERIMENTAL]
227 IO::AIO::min_fdlimit $nfd [EXPERIMENTAL]
221 228
222 IO::AIO::sendfile $ofh, $ifh, $offset, $count 229 IO::AIO::sendfile $ofh, $ifh, $offset, $count
223 IO::AIO::fadvise $fh, $offset, $len, $advice 230 IO::AIO::fadvise $fh, $offset, $len, $advice
224 IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]] 231 IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
225 IO::AIO::munmap $scalar 232 IO::AIO::munmap $scalar
233 IO::AIO::mremap $scalar, $new_length, $flags[, $new_address]
226 IO::AIO::madvise $scalar, $offset, $length, $advice 234 IO::AIO::madvise $scalar, $offset, $length, $advice
227 IO::AIO::mprotect $scalar, $offset, $length, $protect 235 IO::AIO::mprotect $scalar, $offset, $length, $protect
228 IO::AIO::munlock $scalar, $offset = 0, $length = undef 236 IO::AIO::munlock $scalar, $offset = 0, $length = undef
229 IO::AIO::munlockall 237 IO::AIO::munlockall
230 238
… …
332 "O_APPEND"), the following POSIX and non-POSIX constants are 340 "O_APPEND"), the following POSIX and non-POSIX constants are
333 available (missing ones on your system are, as usual, 0): 341 available (missing ones on your system are, as usual, 0):
334 342
335 "O_ASYNC", "O_DIRECT", "O_NOATIME", "O_CLOEXEC", "O_NOCTTY", 343 "O_ASYNC", "O_DIRECT", "O_NOATIME", "O_CLOEXEC", "O_NOCTTY",
336 "O_NOFOLLOW", "O_NONBLOCK", "O_EXEC", "O_SEARCH", "O_DIRECTORY", 344 "O_NOFOLLOW", "O_NONBLOCK", "O_EXEC", "O_SEARCH", "O_DIRECTORY",
337 "O_DSYNC", "O_RSYNC", "O_SYNC", "O_PATH", "O_TMPFILE", and 345 "O_DSYNC", "O_RSYNC", "O_SYNC", "O_PATH", "O_TMPFILE", "O_TTY_INIT"
338 "O_TTY_INIT". 346 and "O_ACCMODE".
339 347
340 aio_close $fh, $callback->($status) 348 aio_close $fh, $callback->($status)
341 Asynchronously close a file and call the callback with the result 349 Asynchronously close a file and call the callback with the result
342 code. 350 code.
343 351
… …
373 381
374 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 382 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
375 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 383 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
376 Reads or writes $length bytes from or to the specified $fh and 384 Reads or writes $length bytes from or to the specified $fh and
377 $offset into the scalar given by $data and offset $dataoffset and 385 $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 386 calls the callback with the actual number of bytes transferred (or
379 error, just like the syscall). 387 -1 on error, just like the syscall).
380 388
381 "aio_read" will, like "sysread", shrink or grow the $data scalar to 389 "aio_read" will, like "sysread", shrink or grow the $data scalar to
382 offset plus the actual number of bytes read. 390 offset plus the actual number of bytes read.
383 391
384 If $offset is undefined, then the current file descriptor offset 392 If $offset is undefined, then the current file descriptor offset
… …
441 As native sendfile syscalls (as practically any non-POSIX interface 449 As native sendfile syscalls (as practically any non-POSIX interface
442 hacked together in a hurry to improve benchmark numbers) tend to be 450 hacked together in a hurry to improve benchmark numbers) tend to be
443 rather buggy on many systems, this implementation tries to work 451 rather buggy on many systems, this implementation tries to work
444 around some known bugs in Linux and FreeBSD kernels (probably 452 around some known bugs in Linux and FreeBSD kernels (probably
445 others, too), but that might fail, so you really really should check 453 others, too), but that might fail, so you really really should check
446 the return value of "aio_sendfile" - fewre bytes than expected might 454 the return value of "aio_sendfile" - fewer bytes than expected might
447 have been transferred. 455 have been transferred.
448 456
449 aio_readahead $fh,$offset,$length, $callback->($retval) 457 aio_readahead $fh,$offset,$length, $callback->($retval)
450 "aio_readahead" populates the page cache with data from a file so 458 "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 459 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 463 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 464 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 465 read beyond the end of the file. The current file offset of the file
458 is left unchanged. 466 is left unchanged.
459 467
460 If that syscall doesn't exist (likely if your OS isn't Linux) it 468 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 469 will be emulated by simply reading the data, which would have a
462 similar effect. 470 similar effect.
463 471
464 aio_stat $fh_or_path, $callback->($status) 472 aio_stat $fh_or_path, $callback->($status)
465 aio_lstat $fh, $callback->($status) 473 aio_lstat $fh, $callback->($status)
466 Works like perl's "stat" or "lstat" in void context. The callback 474 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 475 The callback will be called after the stat and the results will be
468 using "stat _" or "-s _" etc... 476 available using "stat _" or "-s _" and other tests (with the
477 exception of "-B" and "-T").
469 478
470 The pathname passed to "aio_stat" must be absolute. See API NOTES, 479 The pathname passed to "aio_stat" must be absolute. See API NOTES,
471 above, for an explanation. 480 above, for an explanation.
472 481
473 Currently, the stats are always 64-bit-stats, i.e. instead of 482 Currently, the stats are always 64-bit-stats, i.e. instead of
… …
481 back on traditional behaviour). 490 back on traditional behaviour).
482 491
483 "S_IFMT", "S_IFIFO", "S_IFCHR", "S_IFBLK", "S_IFLNK", "S_IFREG", 492 "S_IFMT", "S_IFIFO", "S_IFCHR", "S_IFBLK", "S_IFLNK", "S_IFREG",
484 "S_IFDIR", "S_IFWHT", "S_IFSOCK", "IO::AIO::major $dev_t", 493 "S_IFDIR", "S_IFWHT", "S_IFSOCK", "IO::AIO::major $dev_t",
485 "IO::AIO::minor $dev_t", "IO::AIO::makedev $major, $minor". 494 "IO::AIO::minor $dev_t", "IO::AIO::makedev $major, $minor".
495
496 To access higher resolution stat timestamps, see "SUBSECOND STAT
497 TIME ACCESS".
486 498
487 Example: Print the length of /etc/passwd: 499 Example: Print the length of /etc/passwd:
488 500
489 aio_stat "/etc/passwd", sub { 501 aio_stat "/etc/passwd", sub {
490 $_[0] and die "stat failed: $!"; 502 $_[0] and die "stat failed: $!";
… …
532 namemax => 255, 544 namemax => 255,
533 frsize => 1024, 545 frsize => 1024,
534 fsid => 1810 546 fsid => 1810
535 } 547 }
536 548
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) 549 aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
623 Works like perl's "utime" function (including the special case of 550 Works like perl's "utime" function (including the special case of
624 $atime and $mtime being undef). Fractional times are supported if 551 $atime and $mtime being undef). Fractional times are supported if
625 the underlying syscalls support them. 552 the underlying syscalls support them.
626 553
627 When called with a pathname, uses utimes(2) if available, otherwise 554 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 555 available, otherwise utime(2). If called on a file descriptor, uses
629 available, otherwise returns ENOSYS, so this is not portable. 556 futimens(2) or futimes(2) if available, otherwise returns ENOSYS, so
557 this is not portable.
630 558
631 Examples: 559 Examples:
632 560
633 # set atime and mtime to current time (basically touch(1)): 561 # set atime and mtime to current time (basically touch(1)):
634 aio_utime "path", undef, undef; 562 aio_utime "path", undef, undef;
… …
657 $mode is usually 0 or "IO::AIO::FALLOC_FL_KEEP_SIZE" to allocate 585 $mode is usually 0 or "IO::AIO::FALLOC_FL_KEEP_SIZE" to allocate
658 space, or "IO::AIO::FALLOC_FL_PUNCH_HOLE | 586 space, or "IO::AIO::FALLOC_FL_PUNCH_HOLE |
659 IO::AIO::FALLOC_FL_KEEP_SIZE", to deallocate a file range. 587 IO::AIO::FALLOC_FL_KEEP_SIZE", to deallocate a file range.
660 588
661 IO::AIO also supports "FALLOC_FL_COLLAPSE_RANGE", to remove a range 589 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 590 (without leaving a hole), "FALLOC_FL_ZERO_RANGE", to zero a range,
591 "FALLOC_FL_INSERT_RANGE" to insert a range and
592 "FALLOC_FL_UNSHARE_RANGE" to unshare shared blocks (see your
663 (see your fallocate(2) manpage). 593 fallocate(2) manpage).
664 594
665 The file system block size used by "fallocate" is presumably the 595 The file system block size used by "fallocate" is presumably the
666 "f_bsize" returned by "statvfs". 596 "f_bsize" returned by "statvfs", but different filesystems and
597 filetypes can dictate other limitations.
667 598
668 If "fallocate" isn't available or cannot be emulated (currently no 599 If "fallocate" isn't available or cannot be emulated (currently no
669 emulation will be attempted), passes -1 and sets $! to "ENOSYS". 600 emulation will be attempted), passes -1 and sets $! to "ENOSYS".
670 601
671 aio_chmod $fh_or_path, $mode, $callback->($status) 602 aio_chmod $fh_or_path, $mode, $callback->($status)
… …
715 646
716 On systems that support the AIO::WD working directory abstraction 647 On systems that support the AIO::WD working directory abstraction
717 natively, the case "[$wd, "."]" as $srcpath is specialcased - 648 natively, the case "[$wd, "."]" as $srcpath is specialcased -
718 instead of failing, "rename" is called on the absolute path of $wd. 649 instead of failing, "rename" is called on the absolute path of $wd.
719 650
651 aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
652 Basically a version of "aio_rename" with an additional $flags
653 argument. Calling this with "$flags=0" is the same as calling
654 "aio_rename".
655
656 Non-zero flags are currently only supported on GNU/Linux systems
657 that support renameat2. Other systems fail with "ENOSYS" in this
658 case.
659
660 The following constants are available (missing ones are, as usual
661 0), see renameat2(2) for details:
662
663 "IO::AIO::RENAME_NOREPLACE", "IO::AIO::RENAME_EXCHANGE" and
664 "IO::AIO::RENAME_WHITEOUT".
665
720 aio_mkdir $pathname, $mode, $callback->($status) 666 aio_mkdir $pathname, $mode, $callback->($status)
721 Asynchronously mkdir (create) a directory and call the callback with 667 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 668 the result code. $mode will be modified by the umask at the time the
723 request is executed, so do not change your umask. 669 request is executed, so do not change your umask.
724 670
… …
746 The flags are a combination of the following constants, ORed 692 The flags are a combination of the following constants, ORed
747 together (the flags will also be passed to the callback, possibly 693 together (the flags will also be passed to the callback, possibly
748 modified): 694 modified):
749 695
750 IO::AIO::READDIR_DENTS 696 IO::AIO::READDIR_DENTS
751 When this flag is off, then the callback gets an arrayref 697 Normally the callback gets an arrayref consisting of names only
752 consisting of names only (as with "aio_readdir"), otherwise it 698 (as with "aio_readdir"). If this flag is set, then the callback
753 gets an arrayref with "[$name, $type, $inode]" arrayrefs, each 699 gets an arrayref with "[$name, $type, $inode]" arrayrefs, each
754 describing a single directory entry in more detail. 700 describing a single directory entry in more detail:
755 701
756 $name is the name of the entry. 702 $name is the name of the entry.
757 703
758 $type is one of the "IO::AIO::DT_xxx" constants: 704 $type is one of the "IO::AIO::DT_xxx" constants:
759 705
760 "IO::AIO::DT_UNKNOWN", "IO::AIO::DT_FIFO", "IO::AIO::DT_CHR", 706 "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", 707 "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". 708 "IO::AIO::DT_LNK", "IO::AIO::DT_SOCK", "IO::AIO::DT_WHT".
763 709
764 "IO::AIO::DT_UNKNOWN" means just that: readdir does not know. If 710 "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 711 you need to know, you have to run stat yourself. Also, for
766 reasons, the $type scalars are read-only: you can not modify 712 speed/memory reasons, the $type scalars are read-only: you must
767 them. 713 not modify them.
768 714
769 $inode is the inode number (which might not be exact on systems 715 $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 716 with 64 bit inode numbers and 32 bit perls). This field has
771 unspecified content on systems that do not deliver the inode 717 unspecified content on systems that do not deliver the inode
772 information. 718 information.
… …
784 of which names with short names are tried first. 730 of which names with short names are tried first.
785 731
786 IO::AIO::READDIR_STAT_ORDER 732 IO::AIO::READDIR_STAT_ORDER
787 When this flag is set, then the names will be returned in an 733 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 734 order suitable for stat()'ing each one. That is, when you plan
789 to stat() all files in the given directory, then the returned 735 to stat() most or all files in the given directory, then the
790 order will likely be fastest. 736 returned order will likely be faster.
791 737
792 If both this flag and "IO::AIO::READDIR_DIRS_FIRST" are 738 If both this flag and "IO::AIO::READDIR_DIRS_FIRST" are
793 specified, then the likely dirs come first, resulting in a less 739 specified, then the likely dirs come first, resulting in a less
794 optimal stat order. 740 optimal stat order for stat'ing all entries, but likely a more
741 optimal order for finding subdirectories.
795 742
796 IO::AIO::READDIR_FOUND_UNKNOWN 743 IO::AIO::READDIR_FOUND_UNKNOWN
797 This flag should not be set when calling "aio_readdirx". 744 This flag should not be set when calling "aio_readdirx".
798 Instead, it is being set by "aio_readdirx", when any of the 745 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 746 $type's found were "IO::AIO::DT_UNKNOWN". The absence of this
800 flag therefore indicates that all $type's are known, which can 747 flag therefore indicates that all $type's are known, which can
801 be used to speed up some algorithms. 748 be used to speed up some algorithms.
802 749
750 aio_slurp $pathname, $offset, $length, $data, $callback->($status)
751 Opens, reads and closes the given file. The data is put into $data,
752 which is resized as required.
753
754 If $offset is negative, then it is counted from the end of the file.
755
756 If $length is zero, then the remaining length of the file is used.
757 Also, in this case, the same limitations to modifying $data apply as
758 when IO::AIO::mmap is used, i.e. it must only be modified in-place
759 with "substr". If the size of the file is known, specifying a
760 non-zero $length results in a performance advantage.
761
762 This request is similar to the older "aio_load" request, but since
763 it is a single request, it might be more efficient to use.
764
765 Example: load /etc/passwd into $passwd.
766
767 my $passwd;
768 aio_slurp "/etc/passwd", 0, 0, $passwd, sub {
769 $_[0] >= 0
770 or die "/etc/passwd: $!\n";
771
772 printf "/etc/passwd is %d bytes long, and contains:\n", length $passwd;
773 print $passwd;
774 };
775 IO::AIO::flush;
776
803 aio_load $pathname, $data, $callback->($status) 777 aio_load $pathname, $data, $callback->($status)
804 This is a composite request that tries to fully load the given file 778 This is a composite request that tries to fully load the given file
805 into memory. Status is the same as with aio_read. 779 into memory. Status is the same as with aio_read.
780
781 Using "aio_slurp" might be more efficient, as it is a single
782 request.
806 783
807 aio_copy $srcpath, $dstpath, $callback->($status) 784 aio_copy $srcpath, $dstpath, $callback->($status)
808 Try to copy the *file* (directories not supported as either source 785 Try to copy the *file* (directories not supported as either source
809 or destination) from $srcpath to $dstpath and call the callback with 786 or destination) from $srcpath to $dstpath and call the callback with
810 a status of 0 (ok) or -1 (error, see $!). 787 a status of 0 (ok) or -1 (error, see $!).
788
789 Existing destination files will be truncated.
811 790
812 This is a composite request that creates the destination file with 791 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 792 mode 0200 and copies the contents of the source file into it using
814 "aio_sendfile", followed by restoring atime, mtime, access mode and 793 "aio_sendfile", followed by restoring atime, mtime, access mode and
815 uid/gid, in that order. 794 uid/gid, in that order.
… …
832 to efficiently separate the entries of directory $path into two sets 811 to efficiently separate the entries of directory $path into two sets
833 of names, directories you can recurse into (directories), and ones 812 of names, directories you can recurse into (directories), and ones
834 you cannot recurse into (everything else, including symlinks to 813 you cannot recurse into (everything else, including symlinks to
835 directories). 814 directories).
836 815
837 "aio_scandir" is a composite request that creates of many sub 816 "aio_scandir" is a composite request that generates many sub
838 requests_ $maxreq specifies the maximum number of outstanding aio 817 requests. $maxreq specifies the maximum number of outstanding aio
839 requests that this function generates. If it is "<= 0", then a 818 requests that this function generates. If it is "<= 0", then a
840 suitable default will be chosen (currently 4). 819 suitable default will be chosen (currently 4).
841 820
842 On error, the callback is called without arguments, otherwise it 821 On error, the callback is called without arguments, otherwise it
843 receives two array-refs with path-relative entry names. 822 receives two array-refs with path-relative entry names.
… …
908 So in general, you should only use these calls for things that do 887 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 888 (filesystem) I/O, not for things that wait for other events
910 (network, other processes), although if you are careful and know 889 (network, other processes), although if you are careful and know
911 what you are doing, you still can. 890 what you are doing, you still can.
912 891
892 The following constants are available (missing ones are, as usual
893 0):
894
895 "F_DUPFD_CLOEXEC",
896
897 "F_OFD_GETLK", "F_OFD_SETLK", "F_OFD_GETLKW",
898
899 "FIFREEZE", "FITHAW", "FITRIM", "FICLONE", "FICLONERANGE",
900 "FIDEDUPERANGE".
901
902 "FS_IOC_GETFLAGS", "FS_IOC_SETFLAGS", "FS_IOC_GETVERSION",
903 "FS_IOC_SETVERSION", "FS_IOC_FIEMAP".
904
905 "FS_IOC_FSGETXATTR", "FS_IOC_FSSETXATTR",
906 "FS_IOC_SET_ENCRYPTION_POLICY", "FS_IOC_GET_ENCRYPTION_PWSALT",
907 "FS_IOC_GET_ENCRYPTION_POLICY", "FS_KEY_DESCRIPTOR_SIZE".
908
909 "FS_SECRM_FL", "FS_UNRM_FL", "FS_COMPR_FL", "FS_SYNC_FL",
910 "FS_IMMUTABLE_FL", "FS_APPEND_FL", "FS_NODUMP_FL", "FS_NOATIME_FL",
911 "FS_DIRTY_FL", "FS_COMPRBLK_FL", "FS_NOCOMP_FL", "FS_ENCRYPT_FL",
912 "FS_BTREE_FL", "FS_INDEX_FL", "FS_JOURNAL_DATA_FL", "FS_NOTAIL_FL",
913 "FS_DIRSYNC_FL", "FS_TOPDIR_FL", "FS_FL_USER_MODIFIABLE".
914
915 "FS_XFLAG_REALTIME", "FS_XFLAG_PREALLOC", "FS_XFLAG_IMMUTABLE",
916 "FS_XFLAG_APPEND", "FS_XFLAG_SYNC", "FS_XFLAG_NOATIME",
917 "FS_XFLAG_NODUMP", "FS_XFLAG_RTINHERIT", "FS_XFLAG_PROJINHERIT",
918 "FS_XFLAG_NOSYMLINKS", "FS_XFLAG_EXTSIZE", "FS_XFLAG_EXTSZINHERIT",
919 "FS_XFLAG_NODEFRAG", "FS_XFLAG_FILESTREAM", "FS_XFLAG_DAX",
920 "FS_XFLAG_HASATTR",
921
913 aio_sync $callback->($status) 922 aio_sync $callback->($status)
914 Asynchronously call sync and call the callback when finished. 923 Asynchronously call sync and call the callback when finished.
915 924
916 aio_fsync $fh, $callback->($status) 925 aio_fsync $fh, $callback->($status)
917 Asynchronously call fsync on the given filehandle and call the 926 Asynchronously call fsync on the given filehandle and call the
… …
953 Future versions of this function might fall back to other methods 962 Future versions of this function might fall back to other methods
954 when "fsync" on the directory fails (such as calling "sync"). 963 when "fsync" on the directory fails (such as calling "sync").
955 964
956 Passes 0 when everything went ok, and -1 on error. 965 Passes 0 when everything went ok, and -1 on error.
957 966
958 aio_msync $scalar, $offset = 0, $length = undef, flags = 0, 967 aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC,
959 $callback->($status) 968 $callback->($status)
960 This is a rather advanced IO::AIO call, which only works on 969 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 970 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, 971 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 972 note that the scalar must only be modified in-place while an aio
… …
965 974
966 It calls the "msync" function of your OS, if available, with the 975 It calls the "msync" function of your OS, if available, with the
967 memory area starting at $offset in the string and ending $length 976 memory area starting at $offset in the string and ending $length
968 bytes later. If $length is negative, counts from the end, and if 977 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 978 $length is "undef", then it goes till the end of the string. The
970 flags can be a combination of "IO::AIO::MS_ASYNC", 979 flags can be either "IO::AIO::MS_ASYNC" or "IO::AIO::MS_SYNC", plus
971 "IO::AIO::MS_INVALIDATE" and "IO::AIO::MS_SYNC". 980 an optional "IO::AIO::MS_INVALIDATE".
972 981
973 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, 982 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0,
974 $callback->($status) 983 $callback->($status)
975 This is a rather advanced IO::AIO call, which works best on 984 This is a rather advanced IO::AIO call, which works best on
976 mmap(2)ed scalars. 985 mmap(2)ed scalars.
… …
1062 "IO::AIO::FIEMAP_EXTENT_DATA_INLINE", 1071 "IO::AIO::FIEMAP_EXTENT_DATA_INLINE",
1063 "IO::AIO::FIEMAP_EXTENT_DATA_TAIL", 1072 "IO::AIO::FIEMAP_EXTENT_DATA_TAIL",
1064 "IO::AIO::FIEMAP_EXTENT_UNWRITTEN", "IO::AIO::FIEMAP_EXTENT_MERGED" 1073 "IO::AIO::FIEMAP_EXTENT_UNWRITTEN", "IO::AIO::FIEMAP_EXTENT_MERGED"
1065 or "IO::AIO::FIEMAP_EXTENT_SHARED". 1074 or "IO::AIO::FIEMAP_EXTENT_SHARED".
1066 1075
1067 At the time of this writing (Linux 3.2), this requets is unreliable 1076 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 1077 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 1078 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 1079 large number of extents. The code (only) works around all these
1071 is undef. 1080 issues if $count is "undef".
1072 1081
1073 aio_group $callback->(...) 1082 aio_group $callback->(...)
1074 This is a very special aio request: Instead of doing something, it 1083 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 1084 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 1085 to bundle many requests into a single, composite, request with a
… …
1185 There are some caveats: when directories get renamed (or deleted), the 1194 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 1195 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, 1196 nowhere at all), while the directory fd, if available on the system,
1188 will still point to the original directory. Most functions accepting a 1197 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 1198 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 1199 older systems. Some functions (such as "aio_realpath") will always rely
1191 string form of the pathname. 1200 on the string form of the pathname.
1192 1201
1193 So this functionality is mainly useful to get some protection against 1202 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 1203 "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 1204 future reference, and to speed up doing many operations in the same
1196 directory (e.g. when stat'ing all files in a directory). 1205 directory (e.g. when stat'ing all files in a directory).
… …
1444 Strictly equivalent to: 1453 Strictly equivalent to:
1445 1454
1446 IO::AIO::poll_wait, IO::AIO::poll_cb 1455 IO::AIO::poll_wait, IO::AIO::poll_cb
1447 while IO::AIO::nreqs; 1456 while IO::AIO::nreqs;
1448 1457
1458 This function can be useful at program aborts, to make sure
1459 outstanding I/O has been done ("IO::AIO" uses an "END" block which
1460 already calls this function on normal exits), or when you are merely
1461 using "IO::AIO" for its more advanced functions, rather than for
1462 async I/O, e.g.:
1463
1464 my ($dirs, $nondirs);
1465 IO::AIO::aio_scandir "/tmp", 0, sub { ($dirs, $nondirs) = @_ };
1466 IO::AIO::flush;
1467 # $dirs, $nondirs are now set
1468
1449 IO::AIO::max_poll_reqs $nreqs 1469 IO::AIO::max_poll_reqs $nreqs
1450 IO::AIO::max_poll_time $seconds 1470 IO::AIO::max_poll_time $seconds
1451 These set the maximum number of requests (default 0, meaning 1471 These set the maximum number of requests (default 0, meaning
1452 infinity) that are being processed by "IO::AIO::poll_cb" in one 1472 infinity) that are being processed by "IO::AIO::poll_cb" in one
1453 call, respectively the maximum amount of time (default 0, meaning 1473 call, respectively the maximum amount of time (default 0, meaning
… …
1547 This is a very bad function to use in interactive programs because 1567 This is a very bad function to use in interactive programs because
1548 it blocks, and a bad way to reduce concurrency because it is 1568 it blocks, and a bad way to reduce concurrency because it is
1549 inexact: Better use an "aio_group" together with a feed callback. 1569 inexact: Better use an "aio_group" together with a feed callback.
1550 1570
1551 Its main use is in scripts without an event loop - when you want to 1571 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: 1572 stat a lot of files, you can write something like this:
1553 1573
1554 IO::AIO::max_outstanding 32; 1574 IO::AIO::max_outstanding 32;
1555 1575
1556 for my $path (...) { 1576 for my $path (...) {
1557 aio_stat $path , ...; 1577 aio_stat $path , ...;
… …
1586 1606
1587 IO::AIO::npending 1607 IO::AIO::npending
1588 Returns the number of requests currently in the pending state 1608 Returns the number of requests currently in the pending state
1589 (executed, but not yet processed by poll_cb). 1609 (executed, but not yet processed by poll_cb).
1590 1610
1611 SUBSECOND STAT TIME ACCESS
1612 Both "aio_stat"/"aio_lstat" and perl's "stat"/"lstat" functions can
1613 generally find access/modification and change times with subsecond time
1614 accuracy of the system supports it, but perl's built-in functions only
1615 return the integer part.
1616
1617 The following functions return the timestamps of the most recent stat
1618 with subsecond precision on most systems and work both after
1619 "aio_stat"/"aio_lstat" and perl's "stat"/"lstat" calls. Their return
1620 value is only meaningful after a successful "stat"/"lstat" call, or
1621 during/after a successful "aio_stat"/"aio_lstat" callback.
1622
1623 This is similar to the Time::HiRes "stat" functions, but can return full
1624 resolution without rounding and work with standard perl "stat",
1625 alleviating the need to call the special "Time::HiRes" functions, which
1626 do not act like their perl counterparts.
1627
1628 On operating systems or file systems where subsecond time resolution is
1629 not supported or could not be detected, a fractional part of 0 is
1630 returned, so it is always safe to call these functions.
1631
1632 $seconds = IO::AIO::st_atime, IO::AIO::st_mtime, IO::AIO::st_ctime,
1633 IO::AIO::st_btime
1634 Return the access, modication, change or birth time, respectively,
1635 including fractional part. Due to the limited precision of floating
1636 point, the accuracy on most platforms is only a bit better than
1637 milliseconds for times around now - see the *nsec* function family,
1638 below, for full accuracy.
1639
1640 File birth time is only available when the OS and perl support it
1641 (on FreeBSD and NetBSD at the time of this writing, although support
1642 is adaptive, so if your OS/perl gains support, IO::AIO can take
1643 avdantage of it). On systems where it isn't available, 0 is
1644 currently returned, but this might change to "undef" in a future
1645 version.
1646
1647 ($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtime
1648 Returns access, modification, change and birth time all in one go,
1649 and maybe more times in the future version.
1650
1651 $nanoseconds = IO::AIO::st_atimensec, IO::AIO::st_mtimensec,
1652 IO::AIO::st_ctimensec, IO::AIO::st_btimensec
1653 Return the fractional access, modifcation, change or birth time, in
1654 nanoseconds, as an integer in the range 0 to 999999999.
1655
1656 Note that no accessors are provided for access, modification and
1657 change times - you need to get those from "stat _" if required ("int
1658 IO::AIO::st_atime" and so on will *not* generally give you the
1659 correct value).
1660
1661 $seconds = IO::AIO::st_btimesec
1662 The (integral) seconds part of the file birth time, if available.
1663
1664 ($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtimensec
1665 Like the functions above, but returns all four times in one go (and
1666 maybe more in future versions).
1667
1668 $counter = IO::AIO::st_gen
1669 Returns the generation counter of the file. This is only available
1670 on platforms which have this member in their "struct stat" (most
1671 BSDs at the time of this writing) and generally only to the root
1672 usert. If unsupported, 0 is returned, but this might change to
1673 "undef" in a future version.
1674
1675 Example: print the high resolution modification time of /etc, using
1676 "stat", and "IO::AIO::aio_stat".
1677
1678 if (stat "/etc") {
1679 printf "stat(/etc) mtime: %f\n", IO::AIO::st_mtime;
1680 }
1681
1682 IO::AIO::aio_stat "/etc", sub {
1683 $_[0]
1684 and return;
1685
1686 printf "aio_stat(/etc) mtime: %d.%09d\n", (stat _)[9], IO::AIO::st_mtimensec;
1687 };
1688
1689 IO::AIO::flush;
1690
1691 Output of the awbove on my system, showing reduced and full accuracy:
1692
1693 stat(/etc) mtime: 1534043702.020808
1694 aio_stat(/etc) mtime: 1534043702.020807792
1695
1591 MISCELLANEOUS FUNCTIONS 1696 MISCELLANEOUS FUNCTIONS
1592 IO::AIO implements some functions that are useful when you want to use 1697 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 1698 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_*" 1699 "Asynchronous I/O" route. Many of these have an asynchronous "aio_*"
1595 counterpart. 1700 counterpart.
1701
1702 $numfd = IO::AIO::get_fdlimit
1703 This function is *EXPERIMENTAL* and subject to change.
1704
1705 Tries to find the current file descriptor limit and returns it, or
1706 "undef" and sets $! in case of an error. The limit is one larger
1707 than the highest valid file descriptor number.
1708
1709 IO::AIO::min_fdlimit [$numfd]
1710 This function is *EXPERIMENTAL* and subject to change.
1711
1712 Try to increase the current file descriptor limit(s) to at least
1713 $numfd by changing the soft or hard file descriptor resource limit.
1714 If $numfd is missing, it will try to set a very high limit, although
1715 this is not recommended when you know the actual minimum that you
1716 require.
1717
1718 If the limit cannot be raised enough, the function makes a
1719 best-effort attempt to increase the limit as much as possible, using
1720 various tricks, while still failing. You can query the resulting
1721 limit using "IO::AIO::get_fdlimit".
1722
1723 If an error occurs, returns "undef" and sets $!, otherwise returns
1724 true.
1596 1725
1597 IO::AIO::sendfile $ofh, $ifh, $offset, $count 1726 IO::AIO::sendfile $ofh, $ifh, $offset, $count
1598 Calls the "eio_sendfile_sync" function, which is like 1727 Calls the "eio_sendfile_sync" function, which is like
1599 "aio_sendfile", but is blocking (this makes most sense if you know 1728 "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 1729 the input data is likely cached already and the output filehandle is
… …
1617 details). The following advice constants are available: 1746 details). The following advice constants are available:
1618 "IO::AIO::MADV_NORMAL", "IO::AIO::MADV_SEQUENTIAL", 1747 "IO::AIO::MADV_NORMAL", "IO::AIO::MADV_SEQUENTIAL",
1619 "IO::AIO::MADV_RANDOM", "IO::AIO::MADV_WILLNEED", 1748 "IO::AIO::MADV_RANDOM", "IO::AIO::MADV_WILLNEED",
1620 "IO::AIO::MADV_DONTNEED". 1749 "IO::AIO::MADV_DONTNEED".
1621 1750
1751 If $offset is negative, counts from the end. If $length is negative,
1752 the remaining length of the $scalar is used. If possible, $length
1753 will be reduced to fit into the $scalar.
1754
1622 On systems that do not implement "posix_madvise", this function 1755 On systems that do not implement "posix_madvise", this function
1623 returns ENOSYS, otherwise the return value of "posix_madvise". 1756 returns ENOSYS, otherwise the return value of "posix_madvise".
1624 1757
1625 IO::AIO::mprotect $scalar, $offset, $len, $protect 1758 IO::AIO::mprotect $scalar, $offset, $len, $protect
1626 Simply calls the "mprotect" function on the preferably AIO::mmap'ed 1759 Simply calls the "mprotect" function on the preferably AIO::mmap'ed
1627 $scalar (see its manpage for details). The following protect 1760 $scalar (see its manpage for details). The following protect
1628 constants are available: "IO::AIO::PROT_NONE", "IO::AIO::PROT_READ", 1761 constants are available: "IO::AIO::PROT_NONE", "IO::AIO::PROT_READ",
1629 "IO::AIO::PROT_WRITE", "IO::AIO::PROT_EXEC". 1762 "IO::AIO::PROT_WRITE", "IO::AIO::PROT_EXEC".
1630 1763
1764 If $offset is negative, counts from the end. If $length is negative,
1765 the remaining length of the $scalar is used. If possible, $length
1766 will be reduced to fit into the $scalar.
1767
1631 On systems that do not implement "mprotect", this function returns 1768 On systems that do not implement "mprotect", this function returns
1632 ENOSYS, otherwise the return value of "mprotect". 1769 ENOSYS, otherwise the return value of "mprotect".
1633 1770
1634 IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset] 1771 IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1635 Memory-maps a file (or anonymous memory range) and attaches it to 1772 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 1773 the given $scalar, which will act like a string scalar. Returns true
1637 on success, and false otherwise. 1774 on success, and false otherwise.
1638 1775
1776 The scalar must exist, but its contents do not matter - this means
1777 you cannot use a nonexistant array or hash element. When in doubt,
1778 "undef" the scalar first.
1779
1639 The only operations allowed on the scalar are "substr"/"vec" that 1780 The only operations allowed on the mmapped scalar are
1640 don't change the string length, and most read-only operations such 1781 "substr"/"vec", which don't change the string length, and most
1641 as copying it or searching it with regexes and so on. 1782 read-only operations such as copying it or searching it with regexes
1783 and so on.
1642 1784
1643 Anything else is unsafe and will, at best, result in memory leaks. 1785 Anything else is unsafe and will, at best, result in memory leaks.
1644 1786
1645 The memory map associated with the $scalar is automatically removed 1787 The memory map associated with the $scalar is automatically removed
1646 when the $scalar is destroyed, or when the "IO::AIO::mmap" or 1788 when the $scalar is undef'd or destroyed, or when the
1647 "IO::AIO::munmap" functions are called. 1789 "IO::AIO::mmap" or "IO::AIO::munmap" functions are called on it.
1648 1790
1649 This calls the "mmap"(2) function internally. See your system's 1791 This calls the "mmap"(2) function internally. See your system's
1650 manual page for details on the $length, $prot and $flags parameters. 1792 manual page for details on the $length, $prot and $flags parameters.
1651 1793
1652 The $length must be larger than zero and smaller than the actual 1794 The $length must be larger than zero and smaller than the actual
… …
1685 my $fast_md5 = md5 $data; 1827 my $fast_md5 = md5 $data;
1686 1828
1687 IO::AIO::munmap $scalar 1829 IO::AIO::munmap $scalar
1688 Removes a previous mmap and undefines the $scalar. 1830 Removes a previous mmap and undefines the $scalar.
1689 1831
1832 IO::AIO::mremap $scalar, $new_length, $flags = MREMAP_MAYMOVE[,
1833 $new_address = 0]
1834 Calls the Linux-specific mremap(2) system call. The $scalar must
1835 have been mapped by "IO::AIO::mmap", and $flags must currently
1836 either be 0 or "IO::AIO::MREMAP_MAYMOVE".
1837
1838 Returns true if successful, and false otherwise. If the underlying
1839 mmapped region has changed address, then the true value has the
1840 numerical value 1, otherwise it has the numerical value 0:
1841
1842 my $success = IO::AIO::mremap $mmapped, 8192, IO::AIO::MREMAP_MAYMOVE
1843 or die "mremap: $!";
1844
1845 if ($success*1) {
1846 warn "scalar has chanegd address in memory\n";
1847 }
1848
1849 "IO::AIO::MREMAP_FIXED" and the $new_address argument are currently
1850 implemented, but not supported and might go away in a future
1851 version.
1852
1853 On systems where this call is not supported or is not emulated, this
1854 call returns falls and sets $! to "ENOSYS".
1855
1690 IO::AIO::munlock $scalar, $offset = 0, $length = undef 1856 IO::AIO::munlock $scalar, $offset = 0, $length = undef
1691 Calls the "munlock" function, undoing the effects of a previous 1857 Calls the "munlock" function, undoing the effects of a previous
1692 "aio_mlock" call (see its description for details). 1858 "aio_mlock" call (see its description for details).
1693 1859
1694 IO::AIO::munlockall 1860 IO::AIO::munlockall
… …
1738 1904
1739 Please refer to pipe2(2) for more info on the $flags, but at the 1905 Please refer to pipe2(2) for more info on the $flags, but at the
1740 time of this writing, "IO::AIO::O_CLOEXEC", "IO::AIO::O_NONBLOCK" 1906 time of this writing, "IO::AIO::O_CLOEXEC", "IO::AIO::O_NONBLOCK"
1741 and "IO::AIO::O_DIRECT" (Linux 3.4, for packet-based pipes) were 1907 and "IO::AIO::O_DIRECT" (Linux 3.4, for packet-based pipes) were
1742 supported. 1908 supported.
1909
1910 Example: create a pipe race-free w.r.t. threads and fork:
1911
1912 my ($rfh, $wfh) = IO::AIO::pipe2 IO::AIO::O_CLOEXEC
1913 or die "pipe2: $!\n";
1914
1915 $fh = IO::AIO::eventfd [$initval, [$flags]]
1916 This is a direct interface to the Linux eventfd(2) system call. The
1917 (unhelpful) defaults for $initval and $flags are 0 for both.
1918
1919 On success, the new eventfd filehandle is returned, otherwise
1920 returns "undef". If the eventfd syscall is missing, fails with
1921 "ENOSYS".
1922
1923 Please refer to eventfd(2) for more info on this call.
1924
1925 The following symbol flag values are available:
1926 "IO::AIO::EFD_CLOEXEC", "IO::AIO::EFD_NONBLOCK" and
1927 "IO::AIO::EFD_SEMAPHORE" (Linux 2.6.30).
1928
1929 Example: create a new eventfd filehandle:
1930
1931 $fh = IO::AIO::eventfd 0, IO::AIO::O_CLOEXEC
1932 or die "eventfd: $!\n";
1933
1934 $fh = IO::AIO::timerfd_create $clockid[, $flags]
1935 This is a direct interface to the Linux timerfd_create(2) system
1936 call. The (unhelpful) default for $flags is 0.
1937
1938 On success, the new timerfd filehandle is returned, otherwise
1939 returns "undef". If the eventfd syscall is missing, fails with
1940 "ENOSYS".
1941
1942 Please refer to timerfd_create(2) for more info on this call.
1943
1944 The following $clockid values are available:
1945 "IO::AIO::CLOCK_REALTIME", "IO::AIO::CLOCK_MONOTONIC"
1946 "IO::AIO::CLOCK_CLOCK_BOOTTIME" (Linux 3.15)
1947 "IO::AIO::CLOCK_CLOCK_REALTIME_ALARM" (Linux 3.11) and
1948 "IO::AIO::CLOCK_CLOCK_BOOTTIME_ALARM" (Linux 3.11).
1949
1950 The following $flags values are available (Linux 2.6.27):
1951 "IO::AIO::TFD_NONBLOCK" and "IO::AIO::TFD_CLOEXEC".
1952
1953 Example: create a new timerfd and set it to one-second repeated
1954 alarms, then wait for two alarms:
1955
1956 my $fh = IO::AIO::timerfd_create IO::AIO::CLOCK_BOOTTIME, IO::AIO::TFD_CLOEXEC
1957 or die "timerfd_create: $!\n";
1958
1959 defined IO::AIO::timerfd_settime $fh, 0, 1, 1
1960 or die "timerfd_settime: $!\n";
1961
1962 for (1..2) {
1963 8 == sysread $fh, my $buf, 8
1964 or die "timerfd read failure\n";
1965
1966 printf "number of expirations (likely 1): %d\n",
1967 unpack "Q", $buf;
1968 }
1969
1970 ($cur_interval, $cur_value) = IO::AIO::timerfd_settime $fh, $flags,
1971 $new_interval, $nbw_value
1972 This is a direct interface to the Linux timerfd_settime(2) system
1973 call. Please refer to its manpage for more info on this call.
1974
1975 The new itimerspec is specified using two (possibly fractional)
1976 second values, $new_interval and $new_value).
1977
1978 On success, the current interval and value are returned (as per
1979 "timerfd_gettime"). On failure, the empty list is returned.
1980
1981 The following $flags values are available:
1982 "IO::AIO::TFD_TIMER_ABSTIME" and "IO::AIO::TFD_TIMER_CANCEL_ON_SET".
1983
1984 See "IO::AIO::timerfd_create" for a full example.
1985
1986 ($cur_interval, $cur_value) = IO::AIO::timerfd_gettime $fh
1987 This is a direct interface to the Linux timerfd_gettime(2) system
1988 call. Please refer to its manpage for more info on this call.
1989
1990 On success, returns the current values of interval and value for the
1991 given timerfd (as potentially fractional second values). On failure,
1992 the empty list is returned.
1743 1993
1744EVENT LOOP INTEGRATION 1994EVENT LOOP INTEGRATION
1745 It is recommended to use AnyEvent::AIO to integrate IO::AIO 1995 It is recommended to use AnyEvent::AIO to integrate IO::AIO
1746 automatically into many event loops: 1996 automatically into many event loops:
1747 1997
… …
1797 forking, if "IO::AIO" was used in the parent. Calling it while 2047 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. 2048 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) 2049 Calling it at any time will also result in any undefined (by POSIX)
1800 behaviour. 2050 behaviour.
1801 2051
2052 LINUX-SPECIFIC CALLS
2053 When a call is documented as "linux-specific" then this means it
2054 originated on GNU/Linux. "IO::AIO" will usually try to autodetect the
2055 availability and compatibility of such calls regardless of the platform
2056 it is compiled on, so platforms such as FreeBSD which often implement
2057 these calls will work. When in doubt, call them and see if they fail wth
2058 "ENOSYS".
2059
1802 MEMORY USAGE 2060 MEMORY USAGE
1803 Per-request usage: 2061 Per-request usage:
1804 2062
1805 Each aio request uses - depending on your architecture - around 100-200 2063 Each aio request uses - depending on your architecture - around 100-200
1806 bytes of memory. In addition, stat requests need a stat buffer (possibly 2064 bytes of memory. In addition, stat requests need a stat buffer (possibly
… …
1816 In the execution phase, some aio requests require more memory for 2074 In the execution phase, some aio requests require more memory for
1817 temporary buffers, and each thread requires a stack and other data 2075 temporary buffers, and each thread requires a stack and other data
1818 structures (usually around 16k-128k, depending on the OS). 2076 structures (usually around 16k-128k, depending on the OS).
1819 2077
1820KNOWN BUGS 2078KNOWN BUGS
1821 Known bugs will be fixed in the next release. 2079 Known bugs will be fixed in the next release :)
2080
2081KNOWN ISSUES
2082 Calls that try to "import" foreign memory areas (such as "IO::AIO::mmap"
2083 or "IO::AIO::aio_slurp") do not work with generic lvalues, such as
2084 non-created hash slots or other scalars I didn't think of. It's best to
2085 avoid such and either use scalar variables or making sure that the
2086 scalar exists (e.g. by storing "undef") and isn't "funny" (e.g. tied).
2087
2088 I am not sure anything can be done about this, so this is considered a
2089 known issue, rather than a bug.
1822 2090
1823SEE ALSO 2091SEE ALSO
1824 AnyEvent::AIO for easy integration into event loops, Coro::AIO for a 2092 AnyEvent::AIO for easy integration into event loops, Coro::AIO for a
1825 more natural syntax. 2093 more natural syntax.
1826 2094

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