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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
146 the actual aio request is severed and calling its methods will 145 the actual aio request is severed and calling its methods will
147 either do nothing or result in a runtime error). 146 either do nothing or result in a runtime error).
148 147
149FUNCTIONS 148FUNCTIONS
150 QUICK OVERVIEW 149 QUICK OVERVIEW
151 This section simply lists the prototypes of the most important functions 150 This section simply lists the prototypes most of the functions for quick
152 for quick reference. See the following sections for function-by-function 151 reference. See the following sections for function-by-function
153 documentation. 152 documentation.
154 153
155 aio_wd $pathname, $callback->($wd) 154 aio_wd $pathname, $callback->($wd)
156 aio_open $pathname, $flags, $mode, $callback->($fh) 155 aio_open $pathname, $flags, $mode, $callback->($fh)
157 aio_close $fh, $callback->($status) 156 aio_close $fh, $callback->($status)
165 aio_statvfs $fh_or_path, $callback->($statvfs) 164 aio_statvfs $fh_or_path, $callback->($statvfs)
166 aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 165 aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
167 aio_chown $fh_or_path, $uid, $gid, $callback->($status) 166 aio_chown $fh_or_path, $uid, $gid, $callback->($status)
168 aio_chmod $fh_or_path, $mode, $callback->($status) 167 aio_chmod $fh_or_path, $mode, $callback->($status)
169 aio_truncate $fh_or_path, $offset, $callback->($status) 168 aio_truncate $fh_or_path, $offset, $callback->($status)
169 aio_allocate $fh, $mode, $offset, $len, $callback->($status)
170 aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
170 aio_unlink $pathname, $callback->($status) 171 aio_unlink $pathname, $callback->($status)
171 aio_mknod $pathname, $mode, $dev, $callback->($status) 172 aio_mknod $pathname, $mode, $dev, $callback->($status)
172 aio_link $srcpath, $dstpath, $callback->($status) 173 aio_link $srcpath, $dstpath, $callback->($status)
173 aio_symlink $srcpath, $dstpath, $callback->($status) 174 aio_symlink $srcpath, $dstpath, $callback->($status)
174 aio_readlink $pathname, $callback->($link) 175 aio_readlink $pathname, $callback->($link)
175 aio_realpath $pathname, $callback->($link) 176 aio_realpath $pathname, $callback->($path)
176 aio_rename $srcpath, $dstpath, $callback->($status) 177 aio_rename $srcpath, $dstpath, $callback->($status)
177 aio_mkdir $pathname, $mode, $callback->($status) 178 aio_mkdir $pathname, $mode, $callback->($status)
178 aio_rmdir $pathname, $callback->($status) 179 aio_rmdir $pathname, $callback->($status)
179 aio_readdir $pathname, $callback->($entries) 180 aio_readdir $pathname, $callback->($entries)
180 aio_readdirx $pathname, $flags, $callback->($entries, $flags) 181 aio_readdirx $pathname, $flags, $callback->($entries, $flags)
216 IO::AIO::nready 217 IO::AIO::nready
217 IO::AIO::npending 218 IO::AIO::npending
218 219
219 IO::AIO::sendfile $ofh, $ifh, $offset, $count 220 IO::AIO::sendfile $ofh, $ifh, $offset, $count
220 IO::AIO::fadvise $fh, $offset, $len, $advice 221 IO::AIO::fadvise $fh, $offset, $len, $advice
222 IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
223 IO::AIO::munmap $scalar
221 IO::AIO::madvise $scalar, $offset, $length, $advice 224 IO::AIO::madvise $scalar, $offset, $length, $advice
222 IO::AIO::mprotect $scalar, $offset, $length, $protect 225 IO::AIO::mprotect $scalar, $offset, $length, $protect
223 IO::AIO::munlock $scalar, $offset = 0, $length = undef 226 IO::AIO::munlock $scalar, $offset = 0, $length = undef
224 IO::AIO::munlockall 227 IO::AIO::munlockall
225 228
293 Similar to "aioreq_pri", but subtracts the given value from the 296 Similar to "aioreq_pri", but subtracts the given value from the
294 current priority, so the effect is cumulative. 297 current priority, so the effect is cumulative.
295 298
296 aio_open $pathname, $flags, $mode, $callback->($fh) 299 aio_open $pathname, $flags, $mode, $callback->($fh)
297 Asynchronously open or create a file and call the callback with a 300 Asynchronously open or create a file and call the callback with a
298 newly created filehandle for the file. 301 newly created filehandle for the file (or "undef" in case of an
302 error).
299 303
300 The pathname passed to "aio_open" must be absolute. See API NOTES, 304 The pathname passed to "aio_open" must be absolute. See API NOTES,
301 above, for an explanation. 305 above, for an explanation.
302 306
303 The $flags argument is a bitmask. See the "Fcntl" module for a list. 307 The $flags argument is a bitmask. See the "Fcntl" module for a list.
326 "O_APPEND"), the following POSIX and non-POSIX constants are 330 "O_APPEND"), the following POSIX and non-POSIX constants are
327 available (missing ones on your system are, as usual, 0): 331 available (missing ones on your system are, as usual, 0):
328 332
329 "O_ASYNC", "O_DIRECT", "O_NOATIME", "O_CLOEXEC", "O_NOCTTY", 333 "O_ASYNC", "O_DIRECT", "O_NOATIME", "O_CLOEXEC", "O_NOCTTY",
330 "O_NOFOLLOW", "O_NONBLOCK", "O_EXEC", "O_SEARCH", "O_DIRECTORY", 334 "O_NOFOLLOW", "O_NONBLOCK", "O_EXEC", "O_SEARCH", "O_DIRECTORY",
331 "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".
332 337
333 aio_close $fh, $callback->($status) 338 aio_close $fh, $callback->($status)
334 Asynchronously close a file and call the callback with the result 339 Asynchronously close a file and call the callback with the result
335 code. 340 code.
336 341
525 namemax => 255, 530 namemax => 255,
526 frsize => 1024, 531 frsize => 1024,
527 fsid => 1810 532 fsid => 1810
528 } 533 }
529 534
535 Here is a (likely partial - send me updates!) list of fsid values
536 used by Linux - it is safe to hardcode these when $^O is "linux":
537
538 0x0000adf5 adfs
539 0x0000adff affs
540 0x5346414f afs
541 0x09041934 anon-inode filesystem
542 0x00000187 autofs
543 0x42465331 befs
544 0x1badface bfs
545 0x42494e4d binfmt_misc
546 0x9123683e btrfs
547 0x0027e0eb cgroupfs
548 0xff534d42 cifs
549 0x73757245 coda
550 0x012ff7b7 coh
551 0x28cd3d45 cramfs
552 0x453dcd28 cramfs-wend (wrong endianness)
553 0x64626720 debugfs
554 0x00001373 devfs
555 0x00001cd1 devpts
556 0x0000f15f ecryptfs
557 0x00414a53 efs
558 0x0000137d ext
559 0x0000ef53 ext2/ext3/ext4
560 0x0000ef51 ext2
561 0xf2f52010 f2fs
562 0x00004006 fat
563 0x65735546 fuseblk
564 0x65735543 fusectl
565 0x0bad1dea futexfs
566 0x01161970 gfs2
567 0x47504653 gpfs
568 0x00004244 hfs
569 0xf995e849 hpfs
570 0x00c0ffee hostfs
571 0x958458f6 hugetlbfs
572 0x2bad1dea inotifyfs
573 0x00009660 isofs
574 0x000072b6 jffs2
575 0x3153464a jfs
576 0x6b414653 k-afs
577 0x0bd00bd0 lustre
578 0x0000137f minix
579 0x0000138f minix 30 char names
580 0x00002468 minix v2
581 0x00002478 minix v2 30 char names
582 0x00004d5a minix v3
583 0x19800202 mqueue
584 0x00004d44 msdos
585 0x0000564c novell
586 0x00006969 nfs
587 0x6e667364 nfsd
588 0x00003434 nilfs
589 0x5346544e ntfs
590 0x00009fa1 openprom
591 0x7461636F ocfs2
592 0x00009fa0 proc
593 0x6165676c pstorefs
594 0x0000002f qnx4
595 0x68191122 qnx6
596 0x858458f6 ramfs
597 0x52654973 reiserfs
598 0x00007275 romfs
599 0x67596969 rpc_pipefs
600 0x73636673 securityfs
601 0xf97cff8c selinux
602 0x0000517b smb
603 0x534f434b sockfs
604 0x73717368 squashfs
605 0x62656572 sysfs
606 0x012ff7b6 sysv2
607 0x012ff7b5 sysv4
608 0x01021994 tmpfs
609 0x15013346 udf
610 0x00011954 ufs
611 0x54190100 ufs byteswapped
612 0x00009fa2 usbdevfs
613 0x01021997 v9fs
614 0xa501fcf5 vxfs
615 0xabba1974 xenfs
616 0x012ff7b4 xenix
617 0x58465342 xfs
618 0x012fd16d xia
619
530 aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 620 aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
531 Works like perl's "utime" function (including the special case of 621 Works like perl's "utime" function (including the special case of
532 $atime and $mtime being undef). Fractional times are supported if 622 $atime and $mtime being undef). Fractional times are supported if
533 the underlying syscalls support them. 623 the underlying syscalls support them.
534 624
556 aio_chown "path", 0, undef; 646 aio_chown "path", 0, undef;
557 647
558 aio_truncate $fh_or_path, $offset, $callback->($status) 648 aio_truncate $fh_or_path, $offset, $callback->($status)
559 Works like truncate(2) or ftruncate(2). 649 Works like truncate(2) or ftruncate(2).
560 650
651 aio_allocate $fh, $mode, $offset, $len, $callback->($status)
652 Allocates or frees disk space according to the $mode argument. See
653 the linux "fallocate" documentation for details.
654
655 $mode is usually 0 or "IO::AIO::FALLOC_FL_KEEP_SIZE" to allocate
656 space, or "IO::AIO::FALLOC_FL_PUNCH_HOLE |
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).
662
663 The file system block size used by "fallocate" is presumably the
664 "f_bsize" returned by "statvfs".
665
666 If "fallocate" isn't available or cannot be emulated (currently no
667 emulation will be attempted), passes -1 and sets $! to "ENOSYS".
668
561 aio_chmod $fh_or_path, $mode, $callback->($status) 669 aio_chmod $fh_or_path, $mode, $callback->($status)
562 Works like perl's "chmod" function. 670 Works like perl's "chmod" function.
563 671
564 aio_unlink $pathname, $callback->($status) 672 aio_unlink $pathname, $callback->($status)
565 Asynchronously unlink (delete) a file and call the callback with the 673 Asynchronously unlink (delete) a file and call the callback with the
591 the callback. If an error occurs, nothing or undef gets passed to 699 the callback. If an error occurs, nothing or undef gets passed to
592 the callback. 700 the callback.
593 701
594 aio_realpath $pathname, $callback->($path) 702 aio_realpath $pathname, $callback->($path)
595 Asynchronously make the path absolute and resolve any symlinks in 703 Asynchronously make the path absolute and resolve any symlinks in
596 $path. The resulting path only consists of directories (Same as 704 $path. The resulting path only consists of directories (same as
597 Cwd::realpath). 705 Cwd::realpath).
598 706
599 This request can be used to get the absolute path of the current 707 This request can be used to get the absolute path of the current
600 working directory by passing it a path of . (a single dot). 708 working directory by passing it a path of . (a single dot).
601 709
602 aio_rename $srcpath, $dstpath, $callback->($status) 710 aio_rename $srcpath, $dstpath, $callback->($status)
603 Asynchronously rename the object at $srcpath to $dstpath, just as 711 Asynchronously rename the object at $srcpath to $dstpath, just as
604 rename(2) and call the callback with the result code. 712 rename(2) and call the callback with the result code.
713
714 On systems that support the AIO::WD working directory abstraction
715 natively, the case "[$wd, "."]" as $srcpath is specialcased -
716 instead of failing, "rename" is called on the absolute path of $wd.
605 717
606 aio_mkdir $pathname, $mode, $callback->($status) 718 aio_mkdir $pathname, $mode, $callback->($status)
607 Asynchronously mkdir (create) a directory and call the callback with 719 Asynchronously mkdir (create) a directory and call the callback with
608 the result code. $mode will be modified by the umask at the time the 720 the result code. $mode will be modified by the umask at the time the
609 request is executed, so do not change your umask. 721 request is executed, so do not change your umask.
610 722
611 aio_rmdir $pathname, $callback->($status) 723 aio_rmdir $pathname, $callback->($status)
612 Asynchronously rmdir (delete) a directory and call the callback with 724 Asynchronously rmdir (delete) a directory and call the callback with
613 the result code. 725 the result code.
726
727 On systems that support the AIO::WD working directory abstraction
728 natively, the case "[$wd, "."]" is specialcased - instead of
729 failing, "rmdir" is called on the absolute path of $wd.
614 730
615 aio_readdir $pathname, $callback->($entries) 731 aio_readdir $pathname, $callback->($entries)
616 Unlike the POSIX call of the same name, "aio_readdir" reads an 732 Unlike the POSIX call of the same name, "aio_readdir" reads an
617 entire directory (i.e. opendir + readdir + closedir). The entries 733 entire directory (i.e. opendir + readdir + closedir). The entries
618 will not be sorted, and will NOT include the "." and ".." entries. 734 will not be sorted, and will NOT include the "." and ".." entries.
841 957
842 It touches (reads or writes) all memory pages in the specified range 958 It touches (reads or writes) all memory pages in the specified range
843 inside the scalar. All caveats and parameters are the same as for 959 inside the scalar. All caveats and parameters are the same as for
844 "aio_msync", above, except for flags, which must be either 0 (which 960 "aio_msync", above, except for flags, which must be either 0 (which
845 reads all pages and ensures they are instantiated) or 961 reads all pages and ensures they are instantiated) or
846 "IO::AIO::MT_MODIFY", which modifies the memory page s(by reading 962 "IO::AIO::MT_MODIFY", which modifies the memory pages (by reading
847 and writing an octet from it, which dirties the page). 963 and writing an octet from it, which dirties the page).
848 964
849 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) 965 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
850 This is a rather advanced IO::AIO call, which works best on 966 This is a rather advanced IO::AIO call, which works best on
851 mmap(2)ed scalars. 967 mmap(2)ed scalars.
885 memory. 1001 memory.
886 1002
887 aio_mlockall IO::AIO::MCL_FUTURE; 1003 aio_mlockall IO::AIO::MCL_FUTURE;
888 1004
889 aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents) 1005 aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
890 Queries the extents of the given file (by calling the Linux FIEMAP 1006 Queries the extents of the given file (by calling the Linux "FIEMAP"
891 ioctl, see <http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for 1007 ioctl, see <http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for
892 details). If the "ioctl" is not available on your OS, then this 1008 details). If the ioctl is not available on your OS, then this
893 rquiest will fail with "ENOSYS". 1009 request will fail with "ENOSYS".
894 1010
895 $start is the starting offset to query extents for, $length is the 1011 $start is the starting offset to query extents for, $length is the
896 size of the range to query - if it is "undef", then the whole file 1012 size of the range to query - if it is "undef", then the whole file
897 will be queried. 1013 will be queried.
898 1014
900 "IO::AIO::FIEMAP_FLAG_XATTR" - "IO::AIO::FIEMAP_FLAGS_COMPAT" is 1016 "IO::AIO::FIEMAP_FLAG_XATTR" - "IO::AIO::FIEMAP_FLAGS_COMPAT" is
901 also exported), and is normally 0 or "IO::AIO::FIEMAP_FLAG_SYNC" to 1017 also exported), and is normally 0 or "IO::AIO::FIEMAP_FLAG_SYNC" to
902 query the data portion. 1018 query the data portion.
903 1019
904 $count is the maximum number of extent records to return. If it is 1020 $count is the maximum number of extent records to return. If it is
905 "undef", then IO::AIO queries all extents of the file. As a very 1021 "undef", then IO::AIO queries all extents of the range. As a very
906 special case, if it is 0, then the callback receives the number of 1022 special case, if it is 0, then the callback receives the number of
907 extents instead of the extents themselves. 1023 extents instead of the extents themselves (which is unreliable, see
1024 below).
908 1025
909 If an error occurs, the callback receives no arguments. The special 1026 If an error occurs, the callback receives no arguments. The special
910 "errno" value "IO::AIO::EBADR" is available to test for flag errors. 1027 "errno" value "IO::AIO::EBADR" is available to test for flag errors.
911 1028
912 Otherwise, the callback receives an array reference with extent 1029 Otherwise, the callback receives an array reference with extent
914 the following members: 1031 the following members:
915 1032
916 [$logical, $physical, $length, $flags] 1033 [$logical, $physical, $length, $flags]
917 1034
918 Flags is any combination of the following flag values (typically 1035 Flags is any combination of the following flag values (typically
919 either 0 or "IO::AIO::FIEMAP_EXTENT_LAST"): 1036 either 0 or "IO::AIO::FIEMAP_EXTENT_LAST" (1)):
920 1037
921 "IO::AIO::FIEMAP_EXTENT_LAST", "IO::AIO::FIEMAP_EXTENT_UNKNOWN", 1038 "IO::AIO::FIEMAP_EXTENT_LAST", "IO::AIO::FIEMAP_EXTENT_UNKNOWN",
922 "IO::AIO::FIEMAP_EXTENT_DELALLOC", "IO::AIO::FIEMAP_EXTENT_ENCODED", 1039 "IO::AIO::FIEMAP_EXTENT_DELALLOC", "IO::AIO::FIEMAP_EXTENT_ENCODED",
923 "IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED", 1040 "IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED",
924 "IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED", 1041 "IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED",
925 "IO::AIO::FIEMAP_EXTENT_DATA_INLINE", 1042 "IO::AIO::FIEMAP_EXTENT_DATA_INLINE",
926 "IO::AIO::FIEMAP_EXTENT_DATA_TAIL", 1043 "IO::AIO::FIEMAP_EXTENT_DATA_TAIL",
927 "IO::AIO::FIEMAP_EXTENT_UNWRITTEN", "IO::AIO::FIEMAP_EXTENT_MERGED" 1044 "IO::AIO::FIEMAP_EXTENT_UNWRITTEN", "IO::AIO::FIEMAP_EXTENT_MERGED"
928 or "IO::AIO::FIEMAP_EXTENT_SHARED". 1045 or "IO::AIO::FIEMAP_EXTENT_SHARED".
929 1046
1047 At the time of this writing (Linux 3.2), this requets is unreliable
1048 unless $count is "undef", as the kernel has all sorts of bugs
1049 preventing it to return all extents of a range for files with large
1050 number of extents. The code works around all these issues if $count
1051 is undef.
1052
930 aio_group $callback->(...) 1053 aio_group $callback->(...)
931 This is a very special aio request: Instead of doing something, it 1054 This is a very special aio request: Instead of doing something, it
932 is a container for other aio requests, which is useful if you want 1055 is a container for other aio requests, which is useful if you want
933 to bundle many requests into a single, composite, request with a 1056 to bundle many requests into a single, composite, request with a
934 definite callback and the ability to cancel the whole request with 1057 definite callback and the ability to cancel the whole request with
1013 aio_stat [$etcdir, "passwd"], sub { 1136 aio_stat [$etcdir, "passwd"], sub {
1014 # yay 1137 # yay
1015 }; 1138 };
1016 }; 1139 };
1017 1140
1018 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
1019 an IO::AIO::WD object is itself a potentially blocking operation, which 1142 creating an IO::AIO::WD object is itself a potentially blocking
1020 is why it is done asynchronously. 1143 operation, which is why it is done asynchronously.
1021 1144
1022 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
1023 either of the following three request calls: 1146 either of the following three request calls:
1024 1147
1025 aio_lstat "/etc" , sub { ... # pathname as normal string 1148 aio_lstat "/etc" , sub { ... # pathname as normal string
1045 will still point to the original directory. Most functions accepting a 1168 will still point to the original directory. Most functions accepting a
1046 pathname will use the directory fd on newer systems, and the string on 1169 pathname will use the directory fd on newer systems, and the string on
1047 older systems. Some functions (such as realpath) will always rely on the 1170 older systems. Some functions (such as realpath) will always rely on the
1048 string form of the pathname. 1171 string form of the pathname.
1049 1172
1050 So this fucntionality is mainly useful to get some protection against 1173 So this functionality is mainly useful to get some protection against
1051 "chdir", to easily get an absolute path out of a relative path for 1174 "chdir", to easily get an absolute path out of a relative path for
1052 future reference, and to speed up doing many operations in the same 1175 future reference, and to speed up doing many operations in the same
1053 directory (e.g. when stat'ing all files in a directory). 1176 directory (e.g. when stat'ing all files in a directory).
1054 1177
1055 The following functions implement this working directory abstraction: 1178 The following functions implement this working directory abstraction:
1065 Since passing "undef" as working directory component of a pathname 1188 Since passing "undef" as working directory component of a pathname
1066 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
1067 checking in the "aio_wd" callback, as future requests using the 1190 checking in the "aio_wd" callback, as future requests using the
1068 value will fail in the expected way. 1191 value will fail in the expected way.
1069 1192
1070 If this call isn't available because your OS lacks it or it couldn't
1071 be detected, it will be emulated by calling "fsync" instead.
1072
1073 IO::AIO::CWD 1193 IO::AIO::CWD
1074 This is a compiletime constant (object) that represents the process 1194 This is a compiletime constant (object) that represents the process
1075 current working directory. 1195 current working directory.
1076 1196
1077 Specifying this object as working directory object for a pathname is 1197 Specifying this object as working directory object for a pathname is
1078 as if the pathname would be specified directly, without a directory 1198 as if the pathname would be specified directly, without a directory
1079 object, e.g., these calls are functionally identical: 1199 object. For example, these calls are functionally identical:
1080 1200
1081 aio_stat "somefile", sub { ... }; 1201 aio_stat "somefile", sub { ... };
1082 aio_stat [IO::AIO::CWD, "somefile"], sub { ... }; 1202 aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
1203
1204 To recover the path associated with an IO::AIO::WD object, you can use
1205 "aio_realpath":
1206
1207 aio_realpath $wd, sub {
1208 warn "path is $_[0]\n";
1209 };
1210
1211 Currently, "aio_statvfs" always, and "aio_rename" and "aio_rmdir"
1212 sometimes, fall back to using an absolue path.
1083 1213
1084 IO::AIO::REQ CLASS 1214 IO::AIO::REQ CLASS
1085 All non-aggregate "aio_*" functions return an object of this class when 1215 All non-aggregate "aio_*" functions return an object of this class when
1086 called in non-void context. 1216 called in non-void context.
1087 1217
1239 results. 1369 results.
1240 1370
1241 See "poll_cb" for an example. 1371 See "poll_cb" for an example.
1242 1372
1243 IO::AIO::poll_cb 1373 IO::AIO::poll_cb
1244 Process some outstanding events on the result pipe. You have to call 1374 Process some requests that have reached the result phase (i.e. they
1375 have been executed but the results are not yet reported). You have
1376 to call this "regularly" to finish outstanding requests.
1377
1245 this regularly. Returns 0 if all events could be processed (or there 1378 Returns 0 if all events could be processed (or there were no events
1246 were no events to process), or -1 if it returned earlier for 1379 to process), or -1 if it returned earlier for whatever reason.
1247 whatever reason. Returns immediately when no events are outstanding. 1380 Returns immediately when no events are outstanding. The amount of
1248 The amount of events processed depends on the settings of 1381 events processed depends on the settings of "IO::AIO::max_poll_req",
1249 "IO::AIO::max_poll_req" and "IO::AIO::max_poll_time". 1382 "IO::AIO::max_poll_time" and "IO::AIO::max_outstanding".
1250 1383
1251 If not all requests were processed for whatever reason, the 1384 If not all requests were processed for whatever reason, the poll
1252 filehandle will still be ready when "poll_cb" returns, so normally 1385 file descriptor will still be ready when "poll_cb" returns, so
1253 you don't have to do anything special to have it called later. 1386 normally you don't have to do anything special to have it called
1387 later.
1254 1388
1255 Apart from calling "IO::AIO::poll_cb" when the event filehandle 1389 Apart from calling "IO::AIO::poll_cb" when the event filehandle
1256 becomes ready, it can be beneficial to call this function from loops 1390 becomes ready, it can be beneficial to call this function from loops
1257 which submit a lot of requests, to make sure the results get 1391 which submit a lot of requests, to make sure the results get
1258 processed when they become available and not just when the loop is 1392 processed when they become available and not just when the loop is
1266 Event->io (fd => IO::AIO::poll_fileno, 1400 Event->io (fd => IO::AIO::poll_fileno,
1267 poll => 'r', async => 1, 1401 poll => 'r', async => 1,
1268 cb => \&IO::AIO::poll_cb); 1402 cb => \&IO::AIO::poll_cb);
1269 1403
1270 IO::AIO::poll_wait 1404 IO::AIO::poll_wait
1271 If there are any outstanding requests and none of them in the result 1405 Wait until either at least one request is in the result phase or no
1272 phase, wait till the result filehandle becomes ready for reading 1406 requests are outstanding anymore.
1273 (simply does a "select" on the filehandle. This is useful if you 1407
1274 want to synchronously wait for some requests to finish). 1408 This is useful if you want to synchronously wait for some requests
1409 to become ready, without actually handling them.
1275 1410
1276 See "nreqs" for an example. 1411 See "nreqs" for an example.
1277 1412
1278 IO::AIO::poll 1413 IO::AIO::poll
1279 Waits until some requests have been handled. 1414 Waits until some requests have been handled.
1391 1526
1392 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
1393 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
1394 inexact: Better use an "aio_group" together with a feed callback. 1529 inexact: Better use an "aio_group" together with a feed callback.
1395 1530
1396 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
1397 stat a lot of files, you can write somehting like this: 1532 stat a lot of files, you can write somehting like this:
1398 1533
1399 IO::AIO::max_outstanding 32; 1534 IO::AIO::max_outstanding 32;
1400 1535
1401 for my $path (...) { 1536 for my $path (...) {
1432 IO::AIO::npending 1567 IO::AIO::npending
1433 Returns the number of requests currently in the pending state 1568 Returns the number of requests currently in the pending state
1434 (executed, but not yet processed by poll_cb). 1569 (executed, but not yet processed by poll_cb).
1435 1570
1436 MISCELLANEOUS FUNCTIONS 1571 MISCELLANEOUS FUNCTIONS
1437 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
1438 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.
1439 1576
1440 IO::AIO::sendfile $ofh, $ifh, $offset, $count 1577 IO::AIO::sendfile $ofh, $ifh, $offset, $count
1441 Calls the "eio_sendfile_sync" function, which is like 1578 Calls the "eio_sendfile_sync" function, which is like
1442 "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
1443 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
1474 On systems that do not implement "mprotect", this function returns 1611 On systems that do not implement "mprotect", this function returns
1475 ENOSYS, otherwise the return value of "mprotect". 1612 ENOSYS, otherwise the return value of "mprotect".
1476 1613
1477 IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset] 1614 IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1478 Memory-maps a file (or anonymous memory range) and attaches it to 1615 Memory-maps a file (or anonymous memory range) and attaches it to
1479 the given $scalar, which will act like a string scalar. 1616 the given $scalar, which will act like a string scalar. Returns true
1617 on success, and false otherwise.
1480 1618
1481 The only operations allowed on the scalar are "substr"/"vec" that 1619 The only operations allowed on the scalar are "substr"/"vec" that
1482 don't change the string length, and most read-only operations such 1620 don't change the string length, and most read-only operations such
1483 as copying it or searching it with regexes and so on. 1621 as copying it or searching it with regexes and so on.
1484 1622
1498 "IO::AIO::PROT_EXEC", "IO::AIO::PROT_READ" and/or 1636 "IO::AIO::PROT_EXEC", "IO::AIO::PROT_READ" and/or
1499 "IO::AIO::PROT_WRITE", 1637 "IO::AIO::PROT_WRITE",
1500 1638
1501 $flags can be a combination of "IO::AIO::MAP_SHARED" or 1639 $flags can be a combination of "IO::AIO::MAP_SHARED" or
1502 "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
1503 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
1504 (which is set to "MAP_ANON" if your system only provides this 1642 "MAP_ANON" if your system only provides this constant),
1505 constant), "IO::AIO::MAP_HUGETLB", "IO::AIO::MAP_LOCKED", 1643 "IO::AIO::MAP_HUGETLB", "IO::AIO::MAP_LOCKED",
1506 "IO::AIO::MAP_NORESERVE", "IO::AIO::MAP_POPULATE" or 1644 "IO::AIO::MAP_NORESERVE", "IO::AIO::MAP_POPULATE",
1507 "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".
1508 1648
1509 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.
1510 1650
1511 $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
1512 be a multiple of "IO::AIO::PAGESIZE" and defaults to 0. 1652 be a multiple of "IO::AIO::PAGESIZE" and defaults to 0.
1540 IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags 1680 IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
1541 Calls the GNU/Linux splice(2) syscall, if available. If $r_off or 1681 Calls the GNU/Linux splice(2) syscall, if available. If $r_off or
1542 $w_off are "undef", then "NULL" is passed for these, otherwise they 1682 $w_off are "undef", then "NULL" is passed for these, otherwise they
1543 should be the file offset. 1683 should be the file offset.
1544 1684
1685 $r_fh and $w_fh should not refer to the same file, as splice might
1686 silently corrupt the data in this case.
1687
1545 The following symbol flag values are available: 1688 The following symbol flag values are available:
1546 "IO::AIO::SPLICE_F_MOVE", "IO::AIO::SPLICE_F_NONBLOCK", 1689 "IO::AIO::SPLICE_F_MOVE", "IO::AIO::SPLICE_F_NONBLOCK",
1547 "IO::AIO::SPLICE_F_MORE" and "IO::AIO::SPLICE_F_GIFT". 1690 "IO::AIO::SPLICE_F_MORE" and "IO::AIO::SPLICE_F_GIFT".
1548 1691
1549 See the splice(2) manpage for details. 1692 See the splice(2) manpage for details.
1550 1693
1551 IO::AIO::tee $r_fh, $w_fh, $length, $flags 1694 IO::AIO::tee $r_fh, $w_fh, $length, $flags
1552 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
1553 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.
1554 1723
1555EVENT LOOP INTEGRATION 1724EVENT LOOP INTEGRATION
1556 It is recommended to use AnyEvent::AIO to integrate IO::AIO 1725 It is recommended to use AnyEvent::AIO to integrate IO::AIO
1557 automatically into many event loops: 1726 automatically into many event loops:
1558 1727

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