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Comparing IO-AIO/README (file contents):
Revision 1.55 by root, Sat Jan 25 00:15:52 2014 UTC vs.
Revision 1.58 by root, Sun May 1 17:19:39 2016 UTC

90 90
91 # file contents now in $contents 91 # file contents now in $contents
92 print $contents; 92 print $contents;
93 93
94 # exit event loop and program 94 # exit event loop and program
95 EV::unloop; 95 EV::break;
96 }; 96 };
97 }; 97 };
98 98
99 # possibly queue up other requests, or open GUI windows, 99 # possibly queue up other requests, or open GUI windows,
100 # check for sockets etc. etc. 100 # check for sockets etc. etc.
101 101
102 # process events as long as there are some: 102 # process events as long as there are some:
103 EV::loop; 103 EV::run;
104 104
105REQUEST ANATOMY AND LIFETIME 105REQUEST ANATOMY AND LIFETIME
106 Every "aio_*" function creates a request. which is a C data structure 106 Every "aio_*" function creates a request. which is a C data structure
107 not directly visible to Perl. 107 not directly visible to Perl.
108 108
171 aio_unlink $pathname, $callback->($status) 171 aio_unlink $pathname, $callback->($status)
172 aio_mknod $pathname, $mode, $dev, $callback->($status) 172 aio_mknod $pathname, $mode, $dev, $callback->($status)
173 aio_link $srcpath, $dstpath, $callback->($status) 173 aio_link $srcpath, $dstpath, $callback->($status)
174 aio_symlink $srcpath, $dstpath, $callback->($status) 174 aio_symlink $srcpath, $dstpath, $callback->($status)
175 aio_readlink $pathname, $callback->($link) 175 aio_readlink $pathname, $callback->($link)
176 aio_realpath $pathname, $callback->($link) 176 aio_realpath $pathname, $callback->($path)
177 aio_rename $srcpath, $dstpath, $callback->($status) 177 aio_rename $srcpath, $dstpath, $callback->($status)
178 aio_mkdir $pathname, $mode, $callback->($status) 178 aio_mkdir $pathname, $mode, $callback->($status)
179 aio_rmdir $pathname, $callback->($status) 179 aio_rmdir $pathname, $callback->($status)
180 aio_readdir $pathname, $callback->($entries) 180 aio_readdir $pathname, $callback->($entries)
181 aio_readdirx $pathname, $flags, $callback->($entries, $flags) 181 aio_readdirx $pathname, $flags, $callback->($entries, $flags)
184 aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs) 184 aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
185 aio_load $pathname, $data, $callback->($status) 185 aio_load $pathname, $data, $callback->($status)
186 aio_copy $srcpath, $dstpath, $callback->($status) 186 aio_copy $srcpath, $dstpath, $callback->($status)
187 aio_move $srcpath, $dstpath, $callback->($status) 187 aio_move $srcpath, $dstpath, $callback->($status)
188 aio_rmtree $pathname, $callback->($status) 188 aio_rmtree $pathname, $callback->($status)
189 aio_fcntl $fh, $cmd, $arg, $callback->($status)
190 aio_ioctl $fh, $request, $buf, $callback->($status)
189 aio_sync $callback->($status) 191 aio_sync $callback->($status)
190 aio_syncfs $fh, $callback->($status) 192 aio_syncfs $fh, $callback->($status)
191 aio_fsync $fh, $callback->($status) 193 aio_fsync $fh, $callback->($status)
192 aio_fdatasync $fh, $callback->($status) 194 aio_fdatasync $fh, $callback->($status)
193 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status) 195 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
330 "O_APPEND"), the following POSIX and non-POSIX constants are 332 "O_APPEND"), the following POSIX and non-POSIX constants are
331 available (missing ones on your system are, as usual, 0): 333 available (missing ones on your system are, as usual, 0):
332 334
333 "O_ASYNC", "O_DIRECT", "O_NOATIME", "O_CLOEXEC", "O_NOCTTY", 335 "O_ASYNC", "O_DIRECT", "O_NOATIME", "O_CLOEXEC", "O_NOCTTY",
334 "O_NOFOLLOW", "O_NONBLOCK", "O_EXEC", "O_SEARCH", "O_DIRECTORY", 336 "O_NOFOLLOW", "O_NONBLOCK", "O_EXEC", "O_SEARCH", "O_DIRECTORY",
335 "O_DSYNC", "O_RSYNC", "O_SYNC" and "O_TTY_INIT". 337 "O_DSYNC", "O_RSYNC", "O_SYNC", "O_PATH", "O_TMPFILE", and
338 "O_TTY_INIT".
336 339
337 aio_close $fh, $callback->($status) 340 aio_close $fh, $callback->($status)
338 Asynchronously close a file and call the callback with the result 341 Asynchronously close a file and call the callback with the result
339 code. 342 code.
340 343
553 0x00001373 devfs 556 0x00001373 devfs
554 0x00001cd1 devpts 557 0x00001cd1 devpts
555 0x0000f15f ecryptfs 558 0x0000f15f ecryptfs
556 0x00414a53 efs 559 0x00414a53 efs
557 0x0000137d ext 560 0x0000137d ext
558 0x0000ef53 ext2/ext3 561 0x0000ef53 ext2/ext3/ext4
559 0x0000ef51 ext2 562 0x0000ef51 ext2
563 0xf2f52010 f2fs
560 0x00004006 fat 564 0x00004006 fat
561 0x65735546 fuseblk 565 0x65735546 fuseblk
562 0x65735543 fusectl 566 0x65735543 fusectl
563 0x0bad1dea futexfs 567 0x0bad1dea futexfs
564 0x01161970 gfs2 568 0x01161970 gfs2
565 0x47504653 gpfs 569 0x47504653 gpfs
566 0x00004244 hfs 570 0x00004244 hfs
567 0xf995e849 hpfs 571 0xf995e849 hpfs
572 0x00c0ffee hostfs
568 0x958458f6 hugetlbfs 573 0x958458f6 hugetlbfs
569 0x2bad1dea inotifyfs 574 0x2bad1dea inotifyfs
570 0x00009660 isofs 575 0x00009660 isofs
571 0x000072b6 jffs2 576 0x000072b6 jffs2
572 0x3153464a jfs 577 0x3153464a jfs
587 0x00009fa1 openprom 592 0x00009fa1 openprom
588 0x7461636F ocfs2 593 0x7461636F ocfs2
589 0x00009fa0 proc 594 0x00009fa0 proc
590 0x6165676c pstorefs 595 0x6165676c pstorefs
591 0x0000002f qnx4 596 0x0000002f qnx4
597 0x68191122 qnx6
592 0x858458f6 ramfs 598 0x858458f6 ramfs
593 0x52654973 reiserfs 599 0x52654973 reiserfs
594 0x00007275 romfs 600 0x00007275 romfs
595 0x67596969 rpc_pipefs 601 0x67596969 rpc_pipefs
596 0x73636673 securityfs 602 0x73636673 securityfs
643 649
644 aio_truncate $fh_or_path, $offset, $callback->($status) 650 aio_truncate $fh_or_path, $offset, $callback->($status)
645 Works like truncate(2) or ftruncate(2). 651 Works like truncate(2) or ftruncate(2).
646 652
647 aio_allocate $fh, $mode, $offset, $len, $callback->($status) 653 aio_allocate $fh, $mode, $offset, $len, $callback->($status)
648 Allocates or freed disk space according to the $mode argument. See 654 Allocates or frees disk space according to the $mode argument. See
649 the linux "fallocate" docuemntation for details. 655 the linux "fallocate" documentation for details.
650 656
651 $mode can currently be 0 or "IO::AIO::FALLOC_FL_KEEP_SIZE" to 657 $mode is usually 0 or "IO::AIO::FALLOC_FL_KEEP_SIZE" to allocate
652 allocate space, or "IO::AIO::FALLOC_FL_PUNCH_HOLE | 658 space, or "IO::AIO::FALLOC_FL_PUNCH_HOLE |
653 IO::AIO::FALLOC_FL_KEEP_SIZE", to deallocate a file range. 659 IO::AIO::FALLOC_FL_KEEP_SIZE", to deallocate a file range.
660
661 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
663 (see your fallocate(2) manpage).
654 664
655 The file system block size used by "fallocate" is presumably the 665 The file system block size used by "fallocate" is presumably the
656 "f_bsize" returned by "statvfs". 666 "f_bsize" returned by "statvfs".
657 667
658 If "fallocate" isn't available or cannot be emulated (currently no 668 If "fallocate" isn't available or cannot be emulated (currently no
880 Delete a directory tree starting (and including) $path, return the 890 Delete a directory tree starting (and including) $path, return the
881 status of the final "rmdir" only. This is a composite request that 891 status of the final "rmdir" only. This is a composite request that
882 uses "aio_scandir" to recurse into and rmdir directories, and unlink 892 uses "aio_scandir" to recurse into and rmdir directories, and unlink
883 everything else. 893 everything else.
884 894
895 aio_fcntl $fh, $cmd, $arg, $callback->($status)
896 aio_ioctl $fh, $request, $buf, $callback->($status)
897 These work just like the "fcntl" and "ioctl" built-in functions,
898 except they execute asynchronously and pass the return value to the
899 callback.
900
901 Both calls can be used for a lot of things, some of which make more
902 sense to run asynchronously in their own thread, while some others
903 make less sense. For example, calls that block waiting for external
904 events, such as locking, will also lock down an I/O thread while it
905 is waiting, which can deadlock the whole I/O system. At the same
906 time, there might be no alternative to using a thread to wait.
907
908 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
910 (network, other processes), although if you are careful and know
911 what you are doing, you still can.
912
885 aio_sync $callback->($status) 913 aio_sync $callback->($status)
886 Asynchronously call sync and call the callback when finished. 914 Asynchronously call sync and call the callback when finished.
887 915
888 aio_fsync $fh, $callback->($status) 916 aio_fsync $fh, $callback->($status)
889 Asynchronously call fsync on the given filehandle and call the 917 Asynchronously call fsync on the given filehandle and call the
1128 aio_stat [$etcdir, "passwd"], sub { 1156 aio_stat [$etcdir, "passwd"], sub {
1129 # yay 1157 # yay
1130 }; 1158 };
1131 }; 1159 };
1132 1160
1133 That "aio_wd" is a request and not a normal function shows that creating 1161 The fact that "aio_wd" is a request and not a normal function shows that
1134 an IO::AIO::WD object is itself a potentially blocking operation, which 1162 creating an IO::AIO::WD object is itself a potentially blocking
1135 is why it is done asynchronously. 1163 operation, which is why it is done asynchronously.
1136 1164
1137 To stat the directory obtained with "aio_wd" above, one could write 1165 To stat the directory obtained with "aio_wd" above, one could write
1138 either of the following three request calls: 1166 either of the following three request calls:
1139 1167
1140 aio_lstat "/etc" , sub { ... # pathname as normal string 1168 aio_lstat "/etc" , sub { ... # pathname as normal string
1518 1546
1519 This is a very bad function to use in interactive programs because 1547 This is a very bad function to use in interactive programs because
1520 it blocks, and a bad way to reduce concurrency because it is 1548 it blocks, and a bad way to reduce concurrency because it is
1521 inexact: Better use an "aio_group" together with a feed callback. 1549 inexact: Better use an "aio_group" together with a feed callback.
1522 1550
1523 It's main use is in scripts without an event loop - when you want to 1551 Its main use is in scripts without an event loop - when you want to
1524 stat a lot of files, you can write somehting like this: 1552 stat a lot of files, you can write somehting like this:
1525 1553
1526 IO::AIO::max_outstanding 32; 1554 IO::AIO::max_outstanding 32;
1527 1555
1528 for my $path (...) { 1556 for my $path (...) {
1559 IO::AIO::npending 1587 IO::AIO::npending
1560 Returns the number of requests currently in the pending state 1588 Returns the number of requests currently in the pending state
1561 (executed, but not yet processed by poll_cb). 1589 (executed, but not yet processed by poll_cb).
1562 1590
1563 MISCELLANEOUS FUNCTIONS 1591 MISCELLANEOUS FUNCTIONS
1564 IO::AIO implements some functions that might be useful, but are not 1592 IO::AIO implements some functions that are useful when you want to use
1565 asynchronous. 1593 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_*"
1595 counterpart.
1566 1596
1567 IO::AIO::sendfile $ofh, $ifh, $offset, $count 1597 IO::AIO::sendfile $ofh, $ifh, $offset, $count
1568 Calls the "eio_sendfile_sync" function, which is like 1598 Calls the "eio_sendfile_sync" function, which is like
1569 "aio_sendfile", but is blocking (this makes most sense if you know 1599 "aio_sendfile", but is blocking (this makes most sense if you know
1570 the input data is likely cached already and the output filehandle is 1600 the input data is likely cached already and the output filehandle is
1626 "IO::AIO::PROT_EXEC", "IO::AIO::PROT_READ" and/or 1656 "IO::AIO::PROT_EXEC", "IO::AIO::PROT_READ" and/or
1627 "IO::AIO::PROT_WRITE", 1657 "IO::AIO::PROT_WRITE",
1628 1658
1629 $flags can be a combination of "IO::AIO::MAP_SHARED" or 1659 $flags can be a combination of "IO::AIO::MAP_SHARED" or
1630 "IO::AIO::MAP_PRIVATE", or a number of system-specific flags (when 1660 "IO::AIO::MAP_PRIVATE", or a number of system-specific flags (when
1631 not available, the are defined as 0): "IO::AIO::MAP_ANONYMOUS" 1661 not available, the are 0): "IO::AIO::MAP_ANONYMOUS" (which is set to
1632 (which is set to "MAP_ANON" if your system only provides this 1662 "MAP_ANON" if your system only provides this constant),
1663 "IO::AIO::MAP_LOCKED", "IO::AIO::MAP_NORESERVE",
1633 constant), "IO::AIO::MAP_HUGETLB", "IO::AIO::MAP_LOCKED", 1664 "IO::AIO::MAP_POPULATE", "IO::AIO::MAP_NONBLOCK",
1665 "IO::AIO::MAP_FIXED", "IO::AIO::MAP_GROWSDOWN",
1634 "IO::AIO::MAP_NORESERVE", "IO::AIO::MAP_POPULATE" or 1666 "IO::AIO::MAP_32BIT", "IO::AIO::MAP_HUGETLB" or
1635 "IO::AIO::MAP_NONBLOCK" 1667 "IO::AIO::MAP_STACK".
1636 1668
1637 If $fh is "undef", then a file descriptor of -1 is passed. 1669 If $fh is "undef", then a file descriptor of -1 is passed.
1638 1670
1639 $offset is the offset from the start of the file - it generally must 1671 $offset is the offset from the start of the file - it generally must
1640 be a multiple of "IO::AIO::PAGESIZE" and defaults to 0. 1672 be a multiple of "IO::AIO::PAGESIZE" and defaults to 0.
1678 "IO::AIO::SPLICE_F_MORE" and "IO::AIO::SPLICE_F_GIFT". 1710 "IO::AIO::SPLICE_F_MORE" and "IO::AIO::SPLICE_F_GIFT".
1679 1711
1680 See the splice(2) manpage for details. 1712 See the splice(2) manpage for details.
1681 1713
1682 IO::AIO::tee $r_fh, $w_fh, $length, $flags 1714 IO::AIO::tee $r_fh, $w_fh, $length, $flags
1683 Calls the GNU/Linux tee(2) syscall, see it's manpage and the 1715 Calls the GNU/Linux tee(2) syscall, see its manpage and the
1684 description for "IO::AIO::splice" above for details. 1716 description for "IO::AIO::splice" above for details.
1685 1717
1686 $actual_size = IO::AIO::pipesize $r_fh[, $new_size] 1718 $actual_size = IO::AIO::pipesize $r_fh[, $new_size]
1687 Attempts to query or change the pipe buffer size. Obviously works 1719 Attempts to query or change the pipe buffer size. Obviously works
1688 only on pipes, and currently works only on GNU/Linux systems, and 1720 only on pipes, and currently works only on GNU/Linux systems, and
1689 fails with -1/"ENOSYS" everywhere else. If anybody knows how to 1721 fails with -1/"ENOSYS" everywhere else. If anybody knows how to
1690 influence pipe buffer size on other systems, drop me a note. 1722 influence pipe buffer size on other systems, drop me a note.
1723
1724 ($rfh, $wfh) = IO::AIO::pipe2 [$flags]
1725 This is a direct interface to the Linux pipe2(2) system call. If
1726 $flags is missing or 0, then this should be the same as a call to
1727 perl's built-in "pipe" function and create a new pipe, and works on
1728 systems that lack the pipe2 syscall. On win32, this case invokes
1729 "_pipe (..., 4096, O_BINARY)".
1730
1731 If $flags is non-zero, it tries to invoke the pipe2 system call with
1732 the given flags (Linux 2.6.27, glibc 2.9).
1733
1734 On success, the read and write file handles are returned.
1735
1736 On error, nothing will be returned. If the pipe2 syscall is missing
1737 and $flags is non-zero, fails with "ENOSYS".
1738
1739 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"
1741 and "IO::AIO::O_DIRECT" (Linux 3.4, for packet-based pipes) were
1742 supported.
1691 1743
1692EVENT LOOP INTEGRATION 1744EVENT LOOP INTEGRATION
1693 It is recommended to use AnyEvent::AIO to integrate IO::AIO 1745 It is recommended to use AnyEvent::AIO to integrate IO::AIO
1694 automatically into many event loops: 1746 automatically into many event loops:
1695 1747

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