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Revision 1.50 by root, Sun Oct 9 08:24:49 2011 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
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)
157 aio_seek $fh,$offset,$whence, $callback->($offs)
158 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 158 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
159 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 159 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
160 aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) 160 aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
161 aio_readahead $fh,$offset,$length, $callback->($retval) 161 aio_readahead $fh,$offset,$length, $callback->($retval)
162 aio_stat $fh_or_path, $callback->($status) 162 aio_stat $fh_or_path, $callback->($status)
163 aio_lstat $fh, $callback->($status) 163 aio_lstat $fh, $callback->($status)
164 aio_statvfs $fh_or_path, $callback->($statvfs) 164 aio_statvfs $fh_or_path, $callback->($statvfs)
165 aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 165 aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
166 aio_chown $fh_or_path, $uid, $gid, $callback->($status) 166 aio_chown $fh_or_path, $uid, $gid, $callback->($status)
167 aio_chmod $fh_or_path, $mode, $callback->($status)
167 aio_truncate $fh_or_path, $offset, $callback->($status) 168 aio_truncate $fh_or_path, $offset, $callback->($status)
168 aio_chmod $fh_or_path, $mode, $callback->($status) 169 aio_allocate $fh, $mode, $offset, $len, $callback->($status)
170 aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
169 aio_unlink $pathname, $callback->($status) 171 aio_unlink $pathname, $callback->($status)
170 aio_mknod $pathname, $mode, $dev, $callback->($status) 172 aio_mknod $pathname, $mode, $dev, $callback->($status)
171 aio_link $srcpath, $dstpath, $callback->($status) 173 aio_link $srcpath, $dstpath, $callback->($status)
172 aio_symlink $srcpath, $dstpath, $callback->($status) 174 aio_symlink $srcpath, $dstpath, $callback->($status)
173 aio_readlink $pathname, $callback->($link) 175 aio_readlink $pathname, $callback->($link)
174 aio_realpath $pathname, $callback->($link) 176 aio_realpath $pathname, $callback->($path)
175 aio_rename $srcpath, $dstpath, $callback->($status) 177 aio_rename $srcpath, $dstpath, $callback->($status)
176 aio_mkdir $pathname, $mode, $callback->($status) 178 aio_mkdir $pathname, $mode, $callback->($status)
177 aio_rmdir $pathname, $callback->($status) 179 aio_rmdir $pathname, $callback->($status)
178 aio_readdir $pathname, $callback->($entries) 180 aio_readdir $pathname, $callback->($entries)
179 aio_readdirx $pathname, $flags, $callback->($entries, $flags) 181 aio_readdirx $pathname, $flags, $callback->($entries, $flags)
215 IO::AIO::nready 217 IO::AIO::nready
216 IO::AIO::npending 218 IO::AIO::npending
217 219
218 IO::AIO::sendfile $ofh, $ifh, $offset, $count 220 IO::AIO::sendfile $ofh, $ifh, $offset, $count
219 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
220 IO::AIO::madvise $scalar, $offset, $length, $advice 224 IO::AIO::madvise $scalar, $offset, $length, $advice
221 IO::AIO::mprotect $scalar, $offset, $length, $protect 225 IO::AIO::mprotect $scalar, $offset, $length, $protect
222 IO::AIO::munlock $scalar, $offset = 0, $length = undef 226 IO::AIO::munlock $scalar, $offset = 0, $length = undef
223 IO::AIO::munlockall 227 IO::AIO::munlockall
224 228
225 AIO REQUEST FUNCTIONS 229 API NOTES
226 All the "aio_*" calls are more or less thin wrappers around the syscall 230 All the "aio_*" calls are more or less thin wrappers around the syscall
227 with the same name (sans "aio_"). The arguments are similar or 231 with the same name (sans "aio_"). The arguments are similar or
228 identical, and they all accept an additional (and optional) $callback 232 identical, and they all accept an additional (and optional) $callback
229 argument which must be a code reference. This code reference will be 233 argument which must be a code reference. This code reference will be
230 called after the syscall has been executed in an asynchronous fashion. 234 called after the syscall has been executed in an asynchronous fashion.
260 else to ensure your scalar has the correct contents. 264 else to ensure your scalar has the correct contents.
261 265
262 This works, btw. independent of the internal UTF-8 bit, which IO::AIO 266 This works, btw. independent of the internal UTF-8 bit, which IO::AIO
263 handles correctly whether it is set or not. 267 handles correctly whether it is set or not.
264 268
269 AIO REQUEST FUNCTIONS
265 $prev_pri = aioreq_pri [$pri] 270 $prev_pri = aioreq_pri [$pri]
266 Returns the priority value that would be used for the next request 271 Returns the priority value that would be used for the next request
267 and, if $pri is given, sets the priority for the next aio request. 272 and, if $pri is given, sets the priority for the next aio request.
268 273
269 The default priority is 0, the minimum and maximum priorities are -4 274 The default priority is 0, the minimum and maximum priorities are -4
291 Similar to "aioreq_pri", but subtracts the given value from the 296 Similar to "aioreq_pri", but subtracts the given value from the
292 current priority, so the effect is cumulative. 297 current priority, so the effect is cumulative.
293 298
294 aio_open $pathname, $flags, $mode, $callback->($fh) 299 aio_open $pathname, $flags, $mode, $callback->($fh)
295 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
296 newly created filehandle for the file. 301 newly created filehandle for the file (or "undef" in case of an
302 error).
297 303
298 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,
299 above, for an explanation. 305 above, for an explanation.
300 306
301 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.
324 "O_APPEND"), the following POSIX and non-POSIX constants are 330 "O_APPEND"), the following POSIX and non-POSIX constants are
325 available (missing ones on your system are, as usual, 0): 331 available (missing ones on your system are, as usual, 0):
326 332
327 "O_ASYNC", "O_DIRECT", "O_NOATIME", "O_CLOEXEC", "O_NOCTTY", 333 "O_ASYNC", "O_DIRECT", "O_NOATIME", "O_CLOEXEC", "O_NOCTTY",
328 "O_NOFOLLOW", "O_NONBLOCK", "O_EXEC", "O_SEARCH", "O_DIRECTORY", 334 "O_NOFOLLOW", "O_NONBLOCK", "O_EXEC", "O_SEARCH", "O_DIRECTORY",
329 "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".
330 337
331 aio_close $fh, $callback->($status) 338 aio_close $fh, $callback->($status)
332 Asynchronously close a file and call the callback with the result 339 Asynchronously close a file and call the callback with the result
333 code. 340 code.
334 341
340 will use dup2 to overwrite the file descriptor with the write-end of 347 will use dup2 to overwrite the file descriptor with the write-end of
341 a pipe (the pipe fd will be created on demand and will be cached). 348 a pipe (the pipe fd will be created on demand and will be cached).
342 349
343 Or in other words: the file descriptor will be closed, but it will 350 Or in other words: the file descriptor will be closed, but it will
344 not be free for reuse until the perl filehandle is closed. 351 not be free for reuse until the perl filehandle is closed.
352
353 aio_seek $fh, $offset, $whence, $callback->($offs)
354 Seeks the filehandle to the new $offset, similarly to perl's
355 "sysseek". The $whence can use the traditional values (0 for
356 "IO::AIO::SEEK_SET", 1 for "IO::AIO::SEEK_CUR" or 2 for
357 "IO::AIO::SEEK_END").
358
359 The resulting absolute offset will be passed to the callback, or -1
360 in case of an error.
361
362 In theory, the $whence constants could be different than the
363 corresponding values from Fcntl, but perl guarantees they are the
364 same, so don't panic.
365
366 As a GNU/Linux (and maybe Solaris) extension, also the constants
367 "IO::AIO::SEEK_DATA" and "IO::AIO::SEEK_HOLE" are available, if they
368 could be found. No guarantees about suitability for use in
369 "aio_seek" or Perl's "sysseek" can be made though, although I would
370 naively assume they "just work".
345 371
346 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 372 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
347 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 373 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
348 Reads or writes $length bytes from or to the specified $fh and 374 Reads or writes $length bytes from or to the specified $fh and
349 $offset into the scalar given by $data and offset $dataoffset and 375 $offset into the scalar given by $data and offset $dataoffset and
504 namemax => 255, 530 namemax => 255,
505 frsize => 1024, 531 frsize => 1024,
506 fsid => 1810 532 fsid => 1810
507 } 533 }
508 534
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
509 aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 620 aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
510 Works like perl's "utime" function (including the special case of 621 Works like perl's "utime" function (including the special case of
511 $atime and $mtime being undef). Fractional times are supported if 622 $atime and $mtime being undef). Fractional times are supported if
512 the underlying syscalls support them. 623 the underlying syscalls support them.
513 624
535 aio_chown "path", 0, undef; 646 aio_chown "path", 0, undef;
536 647
537 aio_truncate $fh_or_path, $offset, $callback->($status) 648 aio_truncate $fh_or_path, $offset, $callback->($status)
538 Works like truncate(2) or ftruncate(2). 649 Works like truncate(2) or ftruncate(2).
539 650
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
540 aio_chmod $fh_or_path, $mode, $callback->($status) 669 aio_chmod $fh_or_path, $mode, $callback->($status)
541 Works like perl's "chmod" function. 670 Works like perl's "chmod" function.
542 671
543 aio_unlink $pathname, $callback->($status) 672 aio_unlink $pathname, $callback->($status)
544 Asynchronously unlink (delete) a file and call the callback with the 673 Asynchronously unlink (delete) a file and call the callback with the
570 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
571 the callback. 700 the callback.
572 701
573 aio_realpath $pathname, $callback->($path) 702 aio_realpath $pathname, $callback->($path)
574 Asynchronously make the path absolute and resolve any symlinks in 703 Asynchronously make the path absolute and resolve any symlinks in
575 $path. The resulting path only consists of directories (Same as 704 $path. The resulting path only consists of directories (same as
576 Cwd::realpath). 705 Cwd::realpath).
577 706
578 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
579 working directory by passing it a path of . (a single dot). 708 working directory by passing it a path of . (a single dot).
580 709
581 aio_rename $srcpath, $dstpath, $callback->($status) 710 aio_rename $srcpath, $dstpath, $callback->($status)
582 Asynchronously rename the object at $srcpath to $dstpath, just as 711 Asynchronously rename the object at $srcpath to $dstpath, just as
583 rename(2) and call the callback with the result code. 712 rename(2) and call the callback with the result code.
713
714 On systems that support the AIO::WD working directory abstraction
715 natively, the case "[$wd, "."]" as $srcpath is specialcased -
716 instead of failing, "rename" is called on the absolute path of $wd.
584 717
585 aio_mkdir $pathname, $mode, $callback->($status) 718 aio_mkdir $pathname, $mode, $callback->($status)
586 Asynchronously mkdir (create) a directory and call the callback with 719 Asynchronously mkdir (create) a directory and call the callback with
587 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
588 request is executed, so do not change your umask. 721 request is executed, so do not change your umask.
589 722
590 aio_rmdir $pathname, $callback->($status) 723 aio_rmdir $pathname, $callback->($status)
591 Asynchronously rmdir (delete) a directory and call the callback with 724 Asynchronously rmdir (delete) a directory and call the callback with
592 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.
593 730
594 aio_readdir $pathname, $callback->($entries) 731 aio_readdir $pathname, $callback->($entries)
595 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
596 entire directory (i.e. opendir + readdir + closedir). The entries 733 entire directory (i.e. opendir + readdir + closedir). The entries
597 will not be sorted, and will NOT include the "." and ".." entries. 734 will not be sorted, and will NOT include the "." and ".." entries.
820 957
821 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
822 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
823 "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
824 reads all pages and ensures they are instantiated) or 961 reads all pages and ensures they are instantiated) or
825 "IO::AIO::MT_MODIFY", which modifies the memory page s(by reading 962 "IO::AIO::MT_MODIFY", which modifies the memory pages (by reading
826 and writing an octet from it, which dirties the page). 963 and writing an octet from it, which dirties the page).
827 964
828 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) 965 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
829 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
830 mmap(2)ed scalars. 967 mmap(2)ed scalars.
862 999
863 Example: asynchronously lock all current and future pages into 1000 Example: asynchronously lock all current and future pages into
864 memory. 1001 memory.
865 1002
866 aio_mlockall IO::AIO::MCL_FUTURE; 1003 aio_mlockall IO::AIO::MCL_FUTURE;
1004
1005 aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
1006 Queries the extents of the given file (by calling the Linux "FIEMAP"
1007 ioctl, see <http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for
1008 details). If the ioctl is not available on your OS, then this
1009 request will fail with "ENOSYS".
1010
1011 $start is the starting offset to query extents for, $length is the
1012 size of the range to query - if it is "undef", then the whole file
1013 will be queried.
1014
1015 $flags is a combination of flags ("IO::AIO::FIEMAP_FLAG_SYNC" or
1016 "IO::AIO::FIEMAP_FLAG_XATTR" - "IO::AIO::FIEMAP_FLAGS_COMPAT" is
1017 also exported), and is normally 0 or "IO::AIO::FIEMAP_FLAG_SYNC" to
1018 query the data portion.
1019
1020 $count is the maximum number of extent records to return. If it is
1021 "undef", then IO::AIO queries all extents of the range. As a very
1022 special case, if it is 0, then the callback receives the number of
1023 extents instead of the extents themselves (which is unreliable, see
1024 below).
1025
1026 If an error occurs, the callback receives no arguments. The special
1027 "errno" value "IO::AIO::EBADR" is available to test for flag errors.
1028
1029 Otherwise, the callback receives an array reference with extent
1030 structures. Each extent structure is an array reference itself, with
1031 the following members:
1032
1033 [$logical, $physical, $length, $flags]
1034
1035 Flags is any combination of the following flag values (typically
1036 either 0 or "IO::AIO::FIEMAP_EXTENT_LAST" (1)):
1037
1038 "IO::AIO::FIEMAP_EXTENT_LAST", "IO::AIO::FIEMAP_EXTENT_UNKNOWN",
1039 "IO::AIO::FIEMAP_EXTENT_DELALLOC", "IO::AIO::FIEMAP_EXTENT_ENCODED",
1040 "IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED",
1041 "IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED",
1042 "IO::AIO::FIEMAP_EXTENT_DATA_INLINE",
1043 "IO::AIO::FIEMAP_EXTENT_DATA_TAIL",
1044 "IO::AIO::FIEMAP_EXTENT_UNWRITTEN", "IO::AIO::FIEMAP_EXTENT_MERGED"
1045 or "IO::AIO::FIEMAP_EXTENT_SHARED".
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.
867 1052
868 aio_group $callback->(...) 1053 aio_group $callback->(...)
869 This is a very special aio request: Instead of doing something, it 1054 This is a very special aio request: Instead of doing something, it
870 is a container for other aio requests, which is useful if you want 1055 is a container for other aio requests, which is useful if you want
871 to bundle many requests into a single, composite, request with a 1056 to bundle many requests into a single, composite, request with a
951 aio_stat [$etcdir, "passwd"], sub { 1136 aio_stat [$etcdir, "passwd"], sub {
952 # yay 1137 # yay
953 }; 1138 };
954 }; 1139 };
955 1140
956 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
957 an IO::AIO::WD object is itself a potentially blocking operation, which 1142 creating an IO::AIO::WD object is itself a potentially blocking
958 is why it is done asynchronously. 1143 operation, which is why it is done asynchronously.
959 1144
960 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
961 either of the following three request calls: 1146 either of the following three request calls:
962 1147
963 aio_lstat "/etc" , sub { ... # pathname as normal string 1148 aio_lstat "/etc" , sub { ... # pathname as normal string
983 will still point to the original directory. Most functions accepting a 1168 will still point to the original directory. Most functions accepting a
984 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
985 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
986 string form of the pathname. 1171 string form of the pathname.
987 1172
988 So this fucntionality is mainly useful to get some protection against 1173 So this functionality is mainly useful to get some protection against
989 "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
990 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
991 directory (e.g. when stat'ing all files in a directory). 1176 directory (e.g. when stat'ing all files in a directory).
992 1177
993 The following functions implement this working directory abstraction: 1178 The following functions implement this working directory abstraction:
1003 Since passing "undef" as working directory component of a pathname 1188 Since passing "undef" as working directory component of a pathname
1004 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
1005 checking in the "aio_wd" callback, as future requests using the 1190 checking in the "aio_wd" callback, as future requests using the
1006 value will fail in the expected way. 1191 value will fail in the expected way.
1007 1192
1008 If this call isn't available because your OS lacks it or it couldn't
1009 be detected, it will be emulated by calling "fsync" instead.
1010
1011 IO::AIO::CWD 1193 IO::AIO::CWD
1012 This is a compiletime constant (object) that represents the process 1194 This is a compiletime constant (object) that represents the process
1013 current working directory. 1195 current working directory.
1014 1196
1015 Specifying this object as working directory object for a pathname is 1197 Specifying this object as working directory object for a pathname is
1016 as if the pathname would be specified directly, without a directory 1198 as if the pathname would be specified directly, without a directory
1017 object, e.g., these calls are functionally identical: 1199 object. For example, these calls are functionally identical:
1018 1200
1019 aio_stat "somefile", sub { ... }; 1201 aio_stat "somefile", sub { ... };
1020 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.
1021 1213
1022 IO::AIO::REQ CLASS 1214 IO::AIO::REQ CLASS
1023 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
1024 called in non-void context. 1216 called in non-void context.
1025 1217
1177 results. 1369 results.
1178 1370
1179 See "poll_cb" for an example. 1371 See "poll_cb" for an example.
1180 1372
1181 IO::AIO::poll_cb 1373 IO::AIO::poll_cb
1182 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
1183 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
1184 were no events to process), or -1 if it returned earlier for 1379 to process), or -1 if it returned earlier for whatever reason.
1185 whatever reason. Returns immediately when no events are outstanding. 1380 Returns immediately when no events are outstanding. The amount of
1186 The amount of events processed depends on the settings of 1381 events processed depends on the settings of "IO::AIO::max_poll_req",
1187 "IO::AIO::max_poll_req" and "IO::AIO::max_poll_time". 1382 "IO::AIO::max_poll_time" and "IO::AIO::max_outstanding".
1188 1383
1189 If not all requests were processed for whatever reason, the 1384 If not all requests were processed for whatever reason, the poll
1190 filehandle will still be ready when "poll_cb" returns, so normally 1385 file descriptor will still be ready when "poll_cb" returns, so
1191 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.
1192 1388
1193 Apart from calling "IO::AIO::poll_cb" when the event filehandle 1389 Apart from calling "IO::AIO::poll_cb" when the event filehandle
1194 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
1195 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
1196 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
1204 Event->io (fd => IO::AIO::poll_fileno, 1400 Event->io (fd => IO::AIO::poll_fileno,
1205 poll => 'r', async => 1, 1401 poll => 'r', async => 1,
1206 cb => \&IO::AIO::poll_cb); 1402 cb => \&IO::AIO::poll_cb);
1207 1403
1208 IO::AIO::poll_wait 1404 IO::AIO::poll_wait
1209 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
1210 phase, wait till the result filehandle becomes ready for reading 1406 requests are outstanding anymore.
1211 (simply does a "select" on the filehandle. This is useful if you 1407
1212 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.
1213 1410
1214 See "nreqs" for an example. 1411 See "nreqs" for an example.
1215 1412
1216 IO::AIO::poll 1413 IO::AIO::poll
1217 Waits until some requests have been handled. 1414 Waits until some requests have been handled.
1329 1526
1330 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
1331 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
1332 inexact: Better use an "aio_group" together with a feed callback. 1529 inexact: Better use an "aio_group" together with a feed callback.
1333 1530
1334 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
1335 stat a lot of files, you can write somehting like this: 1532 stat a lot of files, you can write somehting like this:
1336 1533
1337 IO::AIO::max_outstanding 32; 1534 IO::AIO::max_outstanding 32;
1338 1535
1339 for my $path (...) { 1536 for my $path (...) {
1370 IO::AIO::npending 1567 IO::AIO::npending
1371 Returns the number of requests currently in the pending state 1568 Returns the number of requests currently in the pending state
1372 (executed, but not yet processed by poll_cb). 1569 (executed, but not yet processed by poll_cb).
1373 1570
1374 MISCELLANEOUS FUNCTIONS 1571 MISCELLANEOUS FUNCTIONS
1375 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
1376 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.
1377 1576
1378 IO::AIO::sendfile $ofh, $ifh, $offset, $count 1577 IO::AIO::sendfile $ofh, $ifh, $offset, $count
1379 Calls the "eio_sendfile_sync" function, which is like 1578 Calls the "eio_sendfile_sync" function, which is like
1380 "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
1381 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
1412 On systems that do not implement "mprotect", this function returns 1611 On systems that do not implement "mprotect", this function returns
1413 ENOSYS, otherwise the return value of "mprotect". 1612 ENOSYS, otherwise the return value of "mprotect".
1414 1613
1415 IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset] 1614 IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1416 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
1417 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.
1418 1618
1419 The only operations allowed on the scalar are "substr"/"vec" that 1619 The only operations allowed on the scalar are "substr"/"vec" that
1420 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
1421 as copying it or searching it with regexes and so on. 1621 as copying it or searching it with regexes and so on.
1422 1622
1436 "IO::AIO::PROT_EXEC", "IO::AIO::PROT_READ" and/or 1636 "IO::AIO::PROT_EXEC", "IO::AIO::PROT_READ" and/or
1437 "IO::AIO::PROT_WRITE", 1637 "IO::AIO::PROT_WRITE",
1438 1638
1439 $flags can be a combination of "IO::AIO::MAP_SHARED" or 1639 $flags can be a combination of "IO::AIO::MAP_SHARED" or
1440 "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
1441 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
1442 (which is set to "MAP_ANON" if your system only provides this 1642 "MAP_ANON" if your system only provides this constant),
1443 constant), "IO::AIO::MAP_HUGETLB", "IO::AIO::MAP_LOCKED", 1643 "IO::AIO::MAP_HUGETLB", "IO::AIO::MAP_LOCKED",
1444 "IO::AIO::MAP_NORESERVE", "IO::AIO::MAP_POPULATE" or 1644 "IO::AIO::MAP_NORESERVE", "IO::AIO::MAP_POPULATE",
1445 "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".
1446 1648
1447 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.
1448 1650
1449 $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
1450 be a multiple of "IO::AIO::PAGESIZE" and defaults to 0. 1652 be a multiple of "IO::AIO::PAGESIZE" and defaults to 0.
1472 IO::AIO::munlockall 1674 IO::AIO::munlockall
1473 Calls the "munlockall" function. 1675 Calls the "munlockall" function.
1474 1676
1475 On systems that do not implement "munlockall", this function returns 1677 On systems that do not implement "munlockall", this function returns
1476 ENOSYS, otherwise the return value of "munlockall". 1678 ENOSYS, otherwise the return value of "munlockall".
1679
1680 IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
1681 Calls the GNU/Linux splice(2) syscall, if available. If $r_off or
1682 $w_off are "undef", then "NULL" is passed for these, otherwise they
1683 should be the file offset.
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
1688 The following symbol flag values are available:
1689 "IO::AIO::SPLICE_F_MOVE", "IO::AIO::SPLICE_F_NONBLOCK",
1690 "IO::AIO::SPLICE_F_MORE" and "IO::AIO::SPLICE_F_GIFT".
1691
1692 See the splice(2) manpage for details.
1693
1694 IO::AIO::tee $r_fh, $w_fh, $length, $flags
1695 Calls the GNU/Linux tee(2) syscall, see its manpage and the
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.
1477 1723
1478EVENT LOOP INTEGRATION 1724EVENT LOOP INTEGRATION
1479 It is recommended to use AnyEvent::AIO to integrate IO::AIO 1725 It is recommended to use AnyEvent::AIO to integrate IO::AIO
1480 automatically into many event loops: 1726 automatically into many event loops:
1481 1727

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