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Revision 1.54 by root, Sun Jan 6 11:48:14 2013 UTC vs.
Revision 1.57 by root, Mon Jan 18 11:53:09 2016 UTC

64 64
65 EXAMPLE 65 EXAMPLE
66 This is a simple example that uses the EV module and loads /etc/passwd 66 This is a simple example that uses the EV module and loads /etc/passwd
67 asynchronously: 67 asynchronously:
68 68
69 use Fcntl;
70 use EV; 69 use EV;
71 use IO::AIO; 70 use IO::AIO;
72 71
73 # register the IO::AIO callback with EV 72 # register the IO::AIO callback with EV
74 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb; 73 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
91 90
92 # file contents now in $contents 91 # file contents now in $contents
93 print $contents; 92 print $contents;
94 93
95 # exit event loop and program 94 # exit event loop and program
96 EV::unloop; 95 EV::break;
97 }; 96 };
98 }; 97 };
99 98
100 # possibly queue up other requests, or open GUI windows, 99 # possibly queue up other requests, or open GUI windows,
101 # check for sockets etc. etc. 100 # check for sockets etc. etc.
102 101
103 # process events as long as there are some: 102 # process events as long as there are some:
104 EV::loop; 103 EV::run;
105 104
106REQUEST ANATOMY AND LIFETIME 105REQUEST ANATOMY AND LIFETIME
107 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
108 not directly visible to Perl. 107 not directly visible to Perl.
109 108
172 aio_unlink $pathname, $callback->($status) 171 aio_unlink $pathname, $callback->($status)
173 aio_mknod $pathname, $mode, $dev, $callback->($status) 172 aio_mknod $pathname, $mode, $dev, $callback->($status)
174 aio_link $srcpath, $dstpath, $callback->($status) 173 aio_link $srcpath, $dstpath, $callback->($status)
175 aio_symlink $srcpath, $dstpath, $callback->($status) 174 aio_symlink $srcpath, $dstpath, $callback->($status)
176 aio_readlink $pathname, $callback->($link) 175 aio_readlink $pathname, $callback->($link)
177 aio_realpath $pathname, $callback->($link) 176 aio_realpath $pathname, $callback->($path)
178 aio_rename $srcpath, $dstpath, $callback->($status) 177 aio_rename $srcpath, $dstpath, $callback->($status)
179 aio_mkdir $pathname, $mode, $callback->($status) 178 aio_mkdir $pathname, $mode, $callback->($status)
180 aio_rmdir $pathname, $callback->($status) 179 aio_rmdir $pathname, $callback->($status)
181 aio_readdir $pathname, $callback->($entries) 180 aio_readdir $pathname, $callback->($entries)
182 aio_readdirx $pathname, $flags, $callback->($entries, $flags) 181 aio_readdirx $pathname, $flags, $callback->($entries, $flags)
331 "O_APPEND"), the following POSIX and non-POSIX constants are 330 "O_APPEND"), the following POSIX and non-POSIX constants are
332 available (missing ones on your system are, as usual, 0): 331 available (missing ones on your system are, as usual, 0):
333 332
334 "O_ASYNC", "O_DIRECT", "O_NOATIME", "O_CLOEXEC", "O_NOCTTY", 333 "O_ASYNC", "O_DIRECT", "O_NOATIME", "O_CLOEXEC", "O_NOCTTY",
335 "O_NOFOLLOW", "O_NONBLOCK", "O_EXEC", "O_SEARCH", "O_DIRECTORY", 334 "O_NOFOLLOW", "O_NONBLOCK", "O_EXEC", "O_SEARCH", "O_DIRECTORY",
336 "O_DSYNC", "O_RSYNC", "O_SYNC" and "O_TTY_INIT". 335 "O_DSYNC", "O_RSYNC", "O_SYNC", "O_PATH", "O_TMPFILE", and
336 "O_TTY_INIT".
337 337
338 aio_close $fh, $callback->($status) 338 aio_close $fh, $callback->($status)
339 Asynchronously close a file and call the callback with the result 339 Asynchronously close a file and call the callback with the result
340 code. 340 code.
341 341
530 namemax => 255, 530 namemax => 255,
531 frsize => 1024, 531 frsize => 1024,
532 fsid => 1810 532 fsid => 1810
533 } 533 }
534 534
535 Here is a (likely partial) list of fsid values used by Linux - it is 535 Here is a (likely partial - send me updates!) list of fsid values
536 safe to hardcode these when the $^O is "linux": 536 used by Linux - it is safe to hardcode these when $^O is "linux":
537 537
538 0x0000adf5 adfs 538 0x0000adf5 adfs
539 0x0000adff affs 539 0x0000adff affs
540 0x5346414f afs 540 0x5346414f afs
541 0x09041934 anon-inode filesystem 541 0x09041934 anon-inode filesystem
554 0x00001373 devfs 554 0x00001373 devfs
555 0x00001cd1 devpts 555 0x00001cd1 devpts
556 0x0000f15f ecryptfs 556 0x0000f15f ecryptfs
557 0x00414a53 efs 557 0x00414a53 efs
558 0x0000137d ext 558 0x0000137d ext
559 0x0000ef53 ext2/ext3 559 0x0000ef53 ext2/ext3/ext4
560 0x0000ef51 ext2 560 0x0000ef51 ext2
561 0xf2f52010 f2fs
561 0x00004006 fat 562 0x00004006 fat
562 0x65735546 fuseblk 563 0x65735546 fuseblk
563 0x65735543 fusectl 564 0x65735543 fusectl
564 0x0bad1dea futexfs 565 0x0bad1dea futexfs
565 0x01161970 gfs2 566 0x01161970 gfs2
566 0x47504653 gpfs 567 0x47504653 gpfs
567 0x00004244 hfs 568 0x00004244 hfs
568 0xf995e849 hpfs 569 0xf995e849 hpfs
570 0x00c0ffee hostfs
569 0x958458f6 hugetlbfs 571 0x958458f6 hugetlbfs
570 0x2bad1dea inotifyfs 572 0x2bad1dea inotifyfs
571 0x00009660 isofs 573 0x00009660 isofs
572 0x000072b6 jffs2 574 0x000072b6 jffs2
573 0x3153464a jfs 575 0x3153464a jfs
588 0x00009fa1 openprom 590 0x00009fa1 openprom
589 0x7461636F ocfs2 591 0x7461636F ocfs2
590 0x00009fa0 proc 592 0x00009fa0 proc
591 0x6165676c pstorefs 593 0x6165676c pstorefs
592 0x0000002f qnx4 594 0x0000002f qnx4
595 0x68191122 qnx6
593 0x858458f6 ramfs 596 0x858458f6 ramfs
594 0x52654973 reiserfs 597 0x52654973 reiserfs
595 0x00007275 romfs 598 0x00007275 romfs
596 0x67596969 rpc_pipefs 599 0x67596969 rpc_pipefs
597 0x73636673 securityfs 600 0x73636673 securityfs
644 647
645 aio_truncate $fh_or_path, $offset, $callback->($status) 648 aio_truncate $fh_or_path, $offset, $callback->($status)
646 Works like truncate(2) or ftruncate(2). 649 Works like truncate(2) or ftruncate(2).
647 650
648 aio_allocate $fh, $mode, $offset, $len, $callback->($status) 651 aio_allocate $fh, $mode, $offset, $len, $callback->($status)
649 Allocates or freed disk space according to the $mode argument. See 652 Allocates or frees disk space according to the $mode argument. See
650 the linux "fallocate" docuemntation for details. 653 the linux "fallocate" documentation for details.
651 654
652 $mode can currently be 0 or "IO::AIO::FALLOC_FL_KEEP_SIZE" to 655 $mode is usually 0 or "IO::AIO::FALLOC_FL_KEEP_SIZE" to allocate
653 allocate space, or "IO::AIO::FALLOC_FL_PUNCH_HOLE | 656 space, or "IO::AIO::FALLOC_FL_PUNCH_HOLE |
654 IO::AIO::FALLOC_FL_KEEP_SIZE", to deallocate a file range. 657 IO::AIO::FALLOC_FL_KEEP_SIZE", to deallocate a file range.
658
659 IO::AIO also supports "FALLOC_FL_COLLAPSE_RANGE", to remove a range
660 (without leaving a hole) and "FALLOC_FL_ZERO_RANGE", to zero a range
661 (see your fallocate(2) manpage).
655 662
656 The file system block size used by "fallocate" is presumably the 663 The file system block size used by "fallocate" is presumably the
657 "f_bsize" returned by "statvfs". 664 "f_bsize" returned by "statvfs".
658 665
659 If "fallocate" isn't available or cannot be emulated (currently no 666 If "fallocate" isn't available or cannot be emulated (currently no
1129 aio_stat [$etcdir, "passwd"], sub { 1136 aio_stat [$etcdir, "passwd"], sub {
1130 # yay 1137 # yay
1131 }; 1138 };
1132 }; 1139 };
1133 1140
1134 That "aio_wd" is a request and not a normal function shows that creating 1141 The fact that "aio_wd" is a request and not a normal function shows that
1135 an IO::AIO::WD object is itself a potentially blocking operation, which 1142 creating an IO::AIO::WD object is itself a potentially blocking
1136 is why it is done asynchronously. 1143 operation, which is why it is done asynchronously.
1137 1144
1138 To stat the directory obtained with "aio_wd" above, one could write 1145 To stat the directory obtained with "aio_wd" above, one could write
1139 either of the following three request calls: 1146 either of the following three request calls:
1140 1147
1141 aio_lstat "/etc" , sub { ... # pathname as normal string 1148 aio_lstat "/etc" , sub { ... # pathname as normal string
1180 instead of a working directory object and $! is set appropriately. 1187 instead of a working directory object and $! is set appropriately.
1181 Since passing "undef" as working directory component of a pathname 1188 Since passing "undef" as working directory component of a pathname
1182 fails the request with "ENOENT", there is often no need for error 1189 fails the request with "ENOENT", there is often no need for error
1183 checking in the "aio_wd" callback, as future requests using the 1190 checking in the "aio_wd" callback, as future requests using the
1184 value will fail in the expected way. 1191 value will fail in the expected way.
1185
1186 If this call isn't available because your OS lacks it or it couldn't
1187 be detected, it will be emulated by calling "fsync" instead.
1188 1192
1189 IO::AIO::CWD 1193 IO::AIO::CWD
1190 This is a compiletime constant (object) that represents the process 1194 This is a compiletime constant (object) that represents the process
1191 current working directory. 1195 current working directory.
1192 1196
1522 1526
1523 This is a very bad function to use in interactive programs because 1527 This is a very bad function to use in interactive programs because
1524 it blocks, and a bad way to reduce concurrency because it is 1528 it blocks, and a bad way to reduce concurrency because it is
1525 inexact: Better use an "aio_group" together with a feed callback. 1529 inexact: Better use an "aio_group" together with a feed callback.
1526 1530
1527 It's main use is in scripts without an event loop - when you want to 1531 Its main use is in scripts without an event loop - when you want to
1528 stat a lot of files, you can write somehting like this: 1532 stat a lot of files, you can write somehting like this:
1529 1533
1530 IO::AIO::max_outstanding 32; 1534 IO::AIO::max_outstanding 32;
1531 1535
1532 for my $path (...) { 1536 for my $path (...) {
1563 IO::AIO::npending 1567 IO::AIO::npending
1564 Returns the number of requests currently in the pending state 1568 Returns the number of requests currently in the pending state
1565 (executed, but not yet processed by poll_cb). 1569 (executed, but not yet processed by poll_cb).
1566 1570
1567 MISCELLANEOUS FUNCTIONS 1571 MISCELLANEOUS FUNCTIONS
1568 IO::AIO implements some functions that might be useful, but are not 1572 IO::AIO implements some functions that are useful when you want to use
1569 asynchronous. 1573 some "Advanced I/O" function not available to in Perl, without going the
1574 "Asynchronous I/O" route. Many of these have an asynchronous "aio_*"
1575 counterpart.
1570 1576
1571 IO::AIO::sendfile $ofh, $ifh, $offset, $count 1577 IO::AIO::sendfile $ofh, $ifh, $offset, $count
1572 Calls the "eio_sendfile_sync" function, which is like 1578 Calls the "eio_sendfile_sync" function, which is like
1573 "aio_sendfile", but is blocking (this makes most sense if you know 1579 "aio_sendfile", but is blocking (this makes most sense if you know
1574 the input data is likely cached already and the output filehandle is 1580 the input data is likely cached already and the output filehandle is
1630 "IO::AIO::PROT_EXEC", "IO::AIO::PROT_READ" and/or 1636 "IO::AIO::PROT_EXEC", "IO::AIO::PROT_READ" and/or
1631 "IO::AIO::PROT_WRITE", 1637 "IO::AIO::PROT_WRITE",
1632 1638
1633 $flags can be a combination of "IO::AIO::MAP_SHARED" or 1639 $flags can be a combination of "IO::AIO::MAP_SHARED" or
1634 "IO::AIO::MAP_PRIVATE", or a number of system-specific flags (when 1640 "IO::AIO::MAP_PRIVATE", or a number of system-specific flags (when
1635 not available, the are defined as 0): "IO::AIO::MAP_ANONYMOUS" 1641 not available, the are 0): "IO::AIO::MAP_ANONYMOUS" (which is set to
1636 (which is set to "MAP_ANON" if your system only provides this 1642 "MAP_ANON" if your system only provides this constant),
1637 constant), "IO::AIO::MAP_HUGETLB", "IO::AIO::MAP_LOCKED", 1643 "IO::AIO::MAP_HUGETLB", "IO::AIO::MAP_LOCKED",
1638 "IO::AIO::MAP_NORESERVE", "IO::AIO::MAP_POPULATE" or 1644 "IO::AIO::MAP_NORESERVE", "IO::AIO::MAP_POPULATE",
1639 "IO::AIO::MAP_NONBLOCK" 1645 "IO::AIO::MAP_NONBLOCK", "IO::AIO::MAP_FIXED",
1646 "IO::AIO::MAP_GROWSDOWN", "IO::AIO::MAP_32BIT",
1647 "IO::AIO::MAP_HUGETLB" or "IO::AIO::MAP_STACK".
1640 1648
1641 If $fh is "undef", then a file descriptor of -1 is passed. 1649 If $fh is "undef", then a file descriptor of -1 is passed.
1642 1650
1643 $offset is the offset from the start of the file - it generally must 1651 $offset is the offset from the start of the file - it generally must
1644 be a multiple of "IO::AIO::PAGESIZE" and defaults to 0. 1652 be a multiple of "IO::AIO::PAGESIZE" and defaults to 0.
1682 "IO::AIO::SPLICE_F_MORE" and "IO::AIO::SPLICE_F_GIFT". 1690 "IO::AIO::SPLICE_F_MORE" and "IO::AIO::SPLICE_F_GIFT".
1683 1691
1684 See the splice(2) manpage for details. 1692 See the splice(2) manpage for details.
1685 1693
1686 IO::AIO::tee $r_fh, $w_fh, $length, $flags 1694 IO::AIO::tee $r_fh, $w_fh, $length, $flags
1687 Calls the GNU/Linux tee(2) syscall, see it's manpage and the 1695 Calls the GNU/Linux tee(2) syscall, see its manpage and the
1688 description for "IO::AIO::splice" above for details. 1696 description for "IO::AIO::splice" above for details.
1697
1698 $actual_size = IO::AIO::pipesize $r_fh[, $new_size]
1699 Attempts to query or change the pipe buffer size. Obviously works
1700 only on pipes, and currently works only on GNU/Linux systems, and
1701 fails with -1/"ENOSYS" everywhere else. If anybody knows how to
1702 influence pipe buffer size on other systems, drop me a note.
1703
1704 ($rfh, $wfh) = IO::AIO::pipe2 [$flags]
1705 This is a direct interface to the Linux pipe2(2) system call. If
1706 $flags is missing or 0, then this should be the same as a call to
1707 perl's built-in "pipe" function and create a new pipe, and works on
1708 systems that lack the pipe2 syscall. On win32, this case invokes
1709 "_pipe (..., 4096, O_BINARY)".
1710
1711 If $flags is non-zero, it tries to invoke the pipe2 system call with
1712 the given flags (Linux 2.6.27, glibc 2.9).
1713
1714 On success, the read and write file handles are returned.
1715
1716 On error, nothing will be returned. If the pipe2 syscall is missing
1717 and $flags is non-zero, fails with "ENOSYS".
1718
1719 Please refer to pipe2(2) for more info on the $flags, but at the
1720 time of this writing, "IO::AIO::O_CLOEXEC", "IO::AIO::O_NONBLOCK"
1721 and "IO::AIO::O_DIRECT" (Linux 3.4, for packet-based pipes) were
1722 supported.
1689 1723
1690EVENT LOOP INTEGRATION 1724EVENT LOOP INTEGRATION
1691 It is recommended to use AnyEvent::AIO to integrate IO::AIO 1725 It is recommended to use AnyEvent::AIO to integrate IO::AIO
1692 automatically into many event loops: 1726 automatically into many event loops:
1693 1727

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