ViewVC Help
View File | Revision Log | Show Annotations | Download File
/cvs/IO-AIO/README
(Generate patch)

Comparing IO-AIO/README (file contents):
Revision 1.48 by root, Wed Jun 29 11:25:17 2011 UTC vs.
Revision 1.55 by root, Sat Jan 25 00:15:52 2014 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;
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
154 aio_wd $pathname, $callback->($wd)
155 aio_open $pathname, $flags, $mode, $callback->($fh) 155 aio_open $pathname, $flags, $mode, $callback->($fh)
156 aio_close $fh, $callback->($status) 156 aio_close $fh, $callback->($status)
157 aio_seek $fh,$offset,$whence, $callback->($offs)
157 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 158 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
158 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 159 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
159 aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) 160 aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
160 aio_readahead $fh,$offset,$length, $callback->($retval) 161 aio_readahead $fh,$offset,$length, $callback->($retval)
161 aio_stat $fh_or_path, $callback->($status) 162 aio_stat $fh_or_path, $callback->($status)
162 aio_lstat $fh, $callback->($status) 163 aio_lstat $fh, $callback->($status)
163 aio_statvfs $fh_or_path, $callback->($statvfs) 164 aio_statvfs $fh_or_path, $callback->($statvfs)
164 aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 165 aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
165 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)
166 aio_truncate $fh_or_path, $offset, $callback->($status) 168 aio_truncate $fh_or_path, $offset, $callback->($status)
167 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)
168 aio_unlink $pathname, $callback->($status) 171 aio_unlink $pathname, $callback->($status)
169 aio_mknod $path, $mode, $dev, $callback->($status) 172 aio_mknod $pathname, $mode, $dev, $callback->($status)
170 aio_link $srcpath, $dstpath, $callback->($status) 173 aio_link $srcpath, $dstpath, $callback->($status)
171 aio_symlink $srcpath, $dstpath, $callback->($status) 174 aio_symlink $srcpath, $dstpath, $callback->($status)
172 aio_readlink $path, $callback->($link) 175 aio_readlink $pathname, $callback->($link)
176 aio_realpath $pathname, $callback->($link)
173 aio_rename $srcpath, $dstpath, $callback->($status) 177 aio_rename $srcpath, $dstpath, $callback->($status)
174 aio_mkdir $pathname, $mode, $callback->($status) 178 aio_mkdir $pathname, $mode, $callback->($status)
175 aio_rmdir $pathname, $callback->($status) 179 aio_rmdir $pathname, $callback->($status)
176 aio_readdir $pathname, $callback->($entries) 180 aio_readdir $pathname, $callback->($entries)
177 aio_readdirx $pathname, $flags, $callback->($entries, $flags) 181 aio_readdirx $pathname, $flags, $callback->($entries, $flags)
178 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST 182 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
179 IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN 183 IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
184 aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
180 aio_load $path, $data, $callback->($status) 185 aio_load $pathname, $data, $callback->($status)
181 aio_copy $srcpath, $dstpath, $callback->($status) 186 aio_copy $srcpath, $dstpath, $callback->($status)
182 aio_move $srcpath, $dstpath, $callback->($status) 187 aio_move $srcpath, $dstpath, $callback->($status)
183 aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
184 aio_rmtree $path, $callback->($status) 188 aio_rmtree $pathname, $callback->($status)
185 aio_sync $callback->($status) 189 aio_sync $callback->($status)
190 aio_syncfs $fh, $callback->($status)
186 aio_fsync $fh, $callback->($status) 191 aio_fsync $fh, $callback->($status)
187 aio_fdatasync $fh, $callback->($status) 192 aio_fdatasync $fh, $callback->($status)
188 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status) 193 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
189 aio_pathsync $path, $callback->($status) 194 aio_pathsync $pathname, $callback->($status)
190 aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 195 aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
191 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 196 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
192 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) 197 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
193 aio_mlockall $flags, $callback->($status) 198 aio_mlockall $flags, $callback->($status)
194 aio_group $callback->(...) 199 aio_group $callback->(...)
212 IO::AIO::nready 217 IO::AIO::nready
213 IO::AIO::npending 218 IO::AIO::npending
214 219
215 IO::AIO::sendfile $ofh, $ifh, $offset, $count 220 IO::AIO::sendfile $ofh, $ifh, $offset, $count
216 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
217 IO::AIO::madvise $scalar, $offset, $length, $advice 224 IO::AIO::madvise $scalar, $offset, $length, $advice
218 IO::AIO::mprotect $scalar, $offset, $length, $protect 225 IO::AIO::mprotect $scalar, $offset, $length, $protect
219 IO::AIO::munlock $scalar, $offset = 0, $length = undef 226 IO::AIO::munlock $scalar, $offset = 0, $length = undef
220 IO::AIO::munlockall 227 IO::AIO::munlockall
221 228
222 AIO REQUEST FUNCTIONS 229 API NOTES
223 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
224 with the same name (sans "aio_"). The arguments are similar or 231 with the same name (sans "aio_"). The arguments are similar or
225 identical, and they all accept an additional (and optional) $callback 232 identical, and they all accept an additional (and optional) $callback
226 argument which must be a code reference. This code reference will get 233 argument which must be a code reference. This code reference will be
227 called with the syscall return code (e.g. most syscalls return -1 on
228 error, unlike perl, which usually delivers "false") as its sole argument
229 after the given syscall has been executed asynchronously. 234 called after the syscall has been executed in an asynchronous fashion.
235 The results of the request will be passed as arguments to the callback
236 (and, if an error occured, in $!) - for most requests the syscall return
237 code (e.g. most syscalls return -1 on error, unlike perl, which usually
238 delivers "false").
239
240 Some requests (such as "aio_readdir") pass the actual results and
241 communicate failures by passing "undef".
230 242
231 All functions expecting a filehandle keep a copy of the filehandle 243 All functions expecting a filehandle keep a copy of the filehandle
232 internally until the request has finished. 244 internally until the request has finished.
233 245
234 All functions return request objects of type IO::AIO::REQ that allow 246 All functions return request objects of type IO::AIO::REQ that allow
235 further manipulation of those requests while they are in-flight. 247 further manipulation of those requests while they are in-flight.
236 248
237 The pathnames you pass to these routines *must* be absolute and encoded 249 The pathnames you pass to these routines *should* be absolute. The
238 as octets. The reason for the former is that at the time the request is 250 reason for this is that at the time the request is being executed, the
239 being executed, the current working directory could have changed. 251 current working directory could have changed. Alternatively, you can
240 Alternatively, you can make sure that you never change the current 252 make sure that you never change the current working directory anywhere
241 working directory anywhere in the program and then use relative paths. 253 in the program and then use relative paths. You can also take advantage
254 of IO::AIOs working directory abstraction, that lets you specify paths
255 relative to some previously-opened "working directory object" - see the
256 description of the "IO::AIO::WD" class later in this document.
242 257
243 To encode pathnames as octets, either make sure you either: a) always 258 To encode pathnames as octets, either make sure you either: a) always
244 pass in filenames you got from outside (command line, readdir etc.) 259 pass in filenames you got from outside (command line, readdir etc.)
245 without tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module 260 without tinkering, b) are in your native filesystem encoding, c) use the
246 and encode your pathnames to the locale (or other) encoding in effect in 261 Encode module and encode your pathnames to the locale (or other)
247 the user environment, d) use Glib::filename_from_unicode on unicode 262 encoding in effect in the user environment, d) use
248 filenames or e) use something else to ensure your scalar has the correct 263 Glib::filename_from_unicode on unicode filenames or e) use something
249 contents. 264 else to ensure your scalar has the correct contents.
250 265
251 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
252 handles correctly whether it is set or not. 267 handles correctly whether it is set or not.
253 268
269 AIO REQUEST FUNCTIONS
254 $prev_pri = aioreq_pri [$pri] 270 $prev_pri = aioreq_pri [$pri]
255 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
256 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.
257 273
258 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
280 Similar to "aioreq_pri", but subtracts the given value from the 296 Similar to "aioreq_pri", but subtracts the given value from the
281 current priority, so the effect is cumulative. 297 current priority, so the effect is cumulative.
282 298
283 aio_open $pathname, $flags, $mode, $callback->($fh) 299 aio_open $pathname, $flags, $mode, $callback->($fh)
284 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
285 newly created filehandle for the file. 301 newly created filehandle for the file (or "undef" in case of an
302 error).
286 303
287 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,
288 above, for an explanation. 305 above, for an explanation.
289 306
290 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.
329 will use dup2 to overwrite the file descriptor with the write-end of 346 will use dup2 to overwrite the file descriptor with the write-end of
330 a pipe (the pipe fd will be created on demand and will be cached). 347 a pipe (the pipe fd will be created on demand and will be cached).
331 348
332 Or in other words: the file descriptor will be closed, but it will 349 Or in other words: the file descriptor will be closed, but it will
333 not be free for reuse until the perl filehandle is closed. 350 not be free for reuse until the perl filehandle is closed.
351
352 aio_seek $fh, $offset, $whence, $callback->($offs)
353 Seeks the filehandle to the new $offset, similarly to perl's
354 "sysseek". The $whence can use the traditional values (0 for
355 "IO::AIO::SEEK_SET", 1 for "IO::AIO::SEEK_CUR" or 2 for
356 "IO::AIO::SEEK_END").
357
358 The resulting absolute offset will be passed to the callback, or -1
359 in case of an error.
360
361 In theory, the $whence constants could be different than the
362 corresponding values from Fcntl, but perl guarantees they are the
363 same, so don't panic.
364
365 As a GNU/Linux (and maybe Solaris) extension, also the constants
366 "IO::AIO::SEEK_DATA" and "IO::AIO::SEEK_HOLE" are available, if they
367 could be found. No guarantees about suitability for use in
368 "aio_seek" or Perl's "sysseek" can be made though, although I would
369 naively assume they "just work".
334 370
335 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 371 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
336 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 372 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
337 Reads or writes $length bytes from or to the specified $fh and 373 Reads or writes $length bytes from or to the specified $fh and
338 $offset into the scalar given by $data and offset $dataoffset and 374 $offset into the scalar given by $data and offset $dataoffset and
493 namemax => 255, 529 namemax => 255,
494 frsize => 1024, 530 frsize => 1024,
495 fsid => 1810 531 fsid => 1810
496 } 532 }
497 533
534 Here is a (likely partial - send me updates!) list of fsid values
535 used by Linux - it is safe to hardcode these when $^O is "linux":
536
537 0x0000adf5 adfs
538 0x0000adff affs
539 0x5346414f afs
540 0x09041934 anon-inode filesystem
541 0x00000187 autofs
542 0x42465331 befs
543 0x1badface bfs
544 0x42494e4d binfmt_misc
545 0x9123683e btrfs
546 0x0027e0eb cgroupfs
547 0xff534d42 cifs
548 0x73757245 coda
549 0x012ff7b7 coh
550 0x28cd3d45 cramfs
551 0x453dcd28 cramfs-wend (wrong endianness)
552 0x64626720 debugfs
553 0x00001373 devfs
554 0x00001cd1 devpts
555 0x0000f15f ecryptfs
556 0x00414a53 efs
557 0x0000137d ext
558 0x0000ef53 ext2/ext3
559 0x0000ef51 ext2
560 0x00004006 fat
561 0x65735546 fuseblk
562 0x65735543 fusectl
563 0x0bad1dea futexfs
564 0x01161970 gfs2
565 0x47504653 gpfs
566 0x00004244 hfs
567 0xf995e849 hpfs
568 0x958458f6 hugetlbfs
569 0x2bad1dea inotifyfs
570 0x00009660 isofs
571 0x000072b6 jffs2
572 0x3153464a jfs
573 0x6b414653 k-afs
574 0x0bd00bd0 lustre
575 0x0000137f minix
576 0x0000138f minix 30 char names
577 0x00002468 minix v2
578 0x00002478 minix v2 30 char names
579 0x00004d5a minix v3
580 0x19800202 mqueue
581 0x00004d44 msdos
582 0x0000564c novell
583 0x00006969 nfs
584 0x6e667364 nfsd
585 0x00003434 nilfs
586 0x5346544e ntfs
587 0x00009fa1 openprom
588 0x7461636F ocfs2
589 0x00009fa0 proc
590 0x6165676c pstorefs
591 0x0000002f qnx4
592 0x858458f6 ramfs
593 0x52654973 reiserfs
594 0x00007275 romfs
595 0x67596969 rpc_pipefs
596 0x73636673 securityfs
597 0xf97cff8c selinux
598 0x0000517b smb
599 0x534f434b sockfs
600 0x73717368 squashfs
601 0x62656572 sysfs
602 0x012ff7b6 sysv2
603 0x012ff7b5 sysv4
604 0x01021994 tmpfs
605 0x15013346 udf
606 0x00011954 ufs
607 0x54190100 ufs byteswapped
608 0x00009fa2 usbdevfs
609 0x01021997 v9fs
610 0xa501fcf5 vxfs
611 0xabba1974 xenfs
612 0x012ff7b4 xenix
613 0x58465342 xfs
614 0x012fd16d xia
615
498 aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 616 aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
499 Works like perl's "utime" function (including the special case of 617 Works like perl's "utime" function (including the special case of
500 $atime and $mtime being undef). Fractional times are supported if 618 $atime and $mtime being undef). Fractional times are supported if
501 the underlying syscalls support them. 619 the underlying syscalls support them.
502 620
524 aio_chown "path", 0, undef; 642 aio_chown "path", 0, undef;
525 643
526 aio_truncate $fh_or_path, $offset, $callback->($status) 644 aio_truncate $fh_or_path, $offset, $callback->($status)
527 Works like truncate(2) or ftruncate(2). 645 Works like truncate(2) or ftruncate(2).
528 646
647 aio_allocate $fh, $mode, $offset, $len, $callback->($status)
648 Allocates or freed disk space according to the $mode argument. See
649 the linux "fallocate" docuemntation for details.
650
651 $mode can currently be 0 or "IO::AIO::FALLOC_FL_KEEP_SIZE" to
652 allocate space, or "IO::AIO::FALLOC_FL_PUNCH_HOLE |
653 IO::AIO::FALLOC_FL_KEEP_SIZE", to deallocate a file range.
654
655 The file system block size used by "fallocate" is presumably the
656 "f_bsize" returned by "statvfs".
657
658 If "fallocate" isn't available or cannot be emulated (currently no
659 emulation will be attempted), passes -1 and sets $! to "ENOSYS".
660
529 aio_chmod $fh_or_path, $mode, $callback->($status) 661 aio_chmod $fh_or_path, $mode, $callback->($status)
530 Works like perl's "chmod" function. 662 Works like perl's "chmod" function.
531 663
532 aio_unlink $pathname, $callback->($status) 664 aio_unlink $pathname, $callback->($status)
533 Asynchronously unlink (delete) a file and call the callback with the 665 Asynchronously unlink (delete) a file and call the callback with the
534 result code. 666 result code.
535 667
536 aio_mknod $path, $mode, $dev, $callback->($status) 668 aio_mknod $pathname, $mode, $dev, $callback->($status)
537 [EXPERIMENTAL] 669 [EXPERIMENTAL]
538 670
539 Asynchronously create a device node (or fifo). See mknod(2). 671 Asynchronously create a device node (or fifo). See mknod(2).
540 672
541 The only (POSIX-) portable way of calling this function is: 673 The only (POSIX-) portable way of calling this function is:
542 674
543 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ... 675 aio_mknod $pathname, IO::AIO::S_IFIFO | $mode, 0, sub { ...
544 676
545 See "aio_stat" for info about some potentially helpful extra 677 See "aio_stat" for info about some potentially helpful extra
546 constants and functions. 678 constants and functions.
547 679
548 aio_link $srcpath, $dstpath, $callback->($status) 680 aio_link $srcpath, $dstpath, $callback->($status)
552 aio_symlink $srcpath, $dstpath, $callback->($status) 684 aio_symlink $srcpath, $dstpath, $callback->($status)
553 Asynchronously create a new symbolic link to the existing object at 685 Asynchronously create a new symbolic link to the existing object at
554 $srcpath at the path $dstpath and call the callback with the result 686 $srcpath at the path $dstpath and call the callback with the result
555 code. 687 code.
556 688
557 aio_readlink $path, $callback->($link) 689 aio_readlink $pathname, $callback->($link)
558 Asynchronously read the symlink specified by $path and pass it to 690 Asynchronously read the symlink specified by $path and pass it to
559 the callback. If an error occurs, nothing or undef gets passed to 691 the callback. If an error occurs, nothing or undef gets passed to
560 the callback. 692 the callback.
561 693
694 aio_realpath $pathname, $callback->($path)
695 Asynchronously make the path absolute and resolve any symlinks in
696 $path. The resulting path only consists of directories (same as
697 Cwd::realpath).
698
699 This request can be used to get the absolute path of the current
700 working directory by passing it a path of . (a single dot).
701
562 aio_rename $srcpath, $dstpath, $callback->($status) 702 aio_rename $srcpath, $dstpath, $callback->($status)
563 Asynchronously rename the object at $srcpath to $dstpath, just as 703 Asynchronously rename the object at $srcpath to $dstpath, just as
564 rename(2) and call the callback with the result code. 704 rename(2) and call the callback with the result code.
705
706 On systems that support the AIO::WD working directory abstraction
707 natively, the case "[$wd, "."]" as $srcpath is specialcased -
708 instead of failing, "rename" is called on the absolute path of $wd.
565 709
566 aio_mkdir $pathname, $mode, $callback->($status) 710 aio_mkdir $pathname, $mode, $callback->($status)
567 Asynchronously mkdir (create) a directory and call the callback with 711 Asynchronously mkdir (create) a directory and call the callback with
568 the result code. $mode will be modified by the umask at the time the 712 the result code. $mode will be modified by the umask at the time the
569 request is executed, so do not change your umask. 713 request is executed, so do not change your umask.
570 714
571 aio_rmdir $pathname, $callback->($status) 715 aio_rmdir $pathname, $callback->($status)
572 Asynchronously rmdir (delete) a directory and call the callback with 716 Asynchronously rmdir (delete) a directory and call the callback with
573 the result code. 717 the result code.
574 718
719 On systems that support the AIO::WD working directory abstraction
720 natively, the case "[$wd, "."]" is specialcased - instead of
721 failing, "rmdir" is called on the absolute path of $wd.
722
575 aio_readdir $pathname, $callback->($entries) 723 aio_readdir $pathname, $callback->($entries)
576 Unlike the POSIX call of the same name, "aio_readdir" reads an 724 Unlike the POSIX call of the same name, "aio_readdir" reads an
577 entire directory (i.e. opendir + readdir + closedir). The entries 725 entire directory (i.e. opendir + readdir + closedir). The entries
578 will not be sorted, and will NOT include the "." and ".." entries. 726 will not be sorted, and will NOT include the "." and ".." entries.
579 727
580 The callback is passed a single argument which is either "undef" or 728 The callback is passed a single argument which is either "undef" or
581 an array-ref with the filenames. 729 an array-ref with the filenames.
582 730
583 aio_readdirx $pathname, $flags, $callback->($entries, $flags) 731 aio_readdirx $pathname, $flags, $callback->($entries, $flags)
584 Quite similar to "aio_readdir", but the $flags argument allows to 732 Quite similar to "aio_readdir", but the $flags argument allows one
585 tune behaviour and output format. In case of an error, $entries will 733 to tune behaviour and output format. In case of an error, $entries
586 be "undef". 734 will be "undef".
587 735
588 The flags are a combination of the following constants, ORed 736 The flags are a combination of the following constants, ORed
589 together (the flags will also be passed to the callback, possibly 737 together (the flags will also be passed to the callback, possibly
590 modified): 738 modified):
591 739
636 optimal stat order. 784 optimal stat order.
637 785
638 IO::AIO::READDIR_FOUND_UNKNOWN 786 IO::AIO::READDIR_FOUND_UNKNOWN
639 This flag should not be set when calling "aio_readdirx". 787 This flag should not be set when calling "aio_readdirx".
640 Instead, it is being set by "aio_readdirx", when any of the 788 Instead, it is being set by "aio_readdirx", when any of the
641 $type's found were "IO::AIO::DT_UNKNOWN". The absense of this 789 $type's found were "IO::AIO::DT_UNKNOWN". The absence of this
642 flag therefore indicates that all $type's are known, which can 790 flag therefore indicates that all $type's are known, which can
643 be used to speed up some algorithms. 791 be used to speed up some algorithms.
644 792
645 aio_load $path, $data, $callback->($status) 793 aio_load $pathname, $data, $callback->($status)
646 This is a composite request that tries to fully load the given file 794 This is a composite request that tries to fully load the given file
647 into memory. Status is the same as with aio_read. 795 into memory. Status is the same as with aio_read.
648 796
649 aio_copy $srcpath, $dstpath, $callback->($status) 797 aio_copy $srcpath, $dstpath, $callback->($status)
650 Try to copy the *file* (directories not supported as either source 798 Try to copy the *file* (directories not supported as either source
667 815
668 This is a composite request that tries to rename(2) the file first; 816 This is a composite request that tries to rename(2) the file first;
669 if rename fails with "EXDEV", it copies the file with "aio_copy" 817 if rename fails with "EXDEV", it copies the file with "aio_copy"
670 and, if that is successful, unlinks the $srcpath. 818 and, if that is successful, unlinks the $srcpath.
671 819
672 aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) 820 aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
673 Scans a directory (similar to "aio_readdir") but additionally tries 821 Scans a directory (similar to "aio_readdir") but additionally tries
674 to efficiently separate the entries of directory $path into two sets 822 to efficiently separate the entries of directory $path into two sets
675 of names, directories you can recurse into (directories), and ones 823 of names, directories you can recurse into (directories), and ones
676 you cannot recurse into (everything else, including symlinks to 824 you cannot recurse into (everything else, including symlinks to
677 directories). 825 directories).
710 Then entries will be sorted into likely directories a non-initial 858 Then entries will be sorted into likely directories a non-initial
711 dot currently) and likely non-directories (see "aio_readdirx"). Then 859 dot currently) and likely non-directories (see "aio_readdirx"). Then
712 every entry plus an appended "/." will be "stat"'ed, likely 860 every entry plus an appended "/." will be "stat"'ed, likely
713 directories first, in order of their inode numbers. If that 861 directories first, in order of their inode numbers. If that
714 succeeds, it assumes that the entry is a directory or a symlink to 862 succeeds, it assumes that the entry is a directory or a symlink to
715 directory (which will be checked seperately). This is often faster 863 directory (which will be checked separately). This is often faster
716 than stat'ing the entry itself because filesystems might detect the 864 than stat'ing the entry itself because filesystems might detect the
717 type of the entry without reading the inode data (e.g. ext2fs 865 type of the entry without reading the inode data (e.g. ext2fs
718 filetype feature), even on systems that cannot return the filetype 866 filetype feature), even on systems that cannot return the filetype
719 information on readdir. 867 information on readdir.
720 868
726 874
727 It will also likely work on non-POSIX filesystems with reduced 875 It will also likely work on non-POSIX filesystems with reduced
728 efficiency as those tend to return 0 or 1 as link counts, which 876 efficiency as those tend to return 0 or 1 as link counts, which
729 disables the directory counting heuristic. 877 disables the directory counting heuristic.
730 878
731 aio_rmtree $path, $callback->($status) 879 aio_rmtree $pathname, $callback->($status)
732 Delete a directory tree starting (and including) $path, return the 880 Delete a directory tree starting (and including) $path, return the
733 status of the final "rmdir" only. This is a composite request that 881 status of the final "rmdir" only. This is a composite request that
734 uses "aio_scandir" to recurse into and rmdir directories, and unlink 882 uses "aio_scandir" to recurse into and rmdir directories, and unlink
735 everything else. 883 everything else.
736 884
745 Asynchronously call fdatasync on the given filehandle and call the 893 Asynchronously call fdatasync on the given filehandle and call the
746 callback with the fdatasync result code. 894 callback with the fdatasync result code.
747 895
748 If this call isn't available because your OS lacks it or it couldn't 896 If this call isn't available because your OS lacks it or it couldn't
749 be detected, it will be emulated by calling "fsync" instead. 897 be detected, it will be emulated by calling "fsync" instead.
898
899 aio_syncfs $fh, $callback->($status)
900 Asynchronously call the syncfs syscall to sync the filesystem
901 associated to the given filehandle and call the callback with the
902 syncfs result code. If syncfs is not available, calls sync(), but
903 returns -1 and sets errno to "ENOSYS" nevertheless.
750 904
751 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status) 905 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
752 Sync the data portion of the file specified by $offset and $length 906 Sync the data portion of the file specified by $offset and $length
753 to disk (but NOT the metadata), by calling the Linux-specific 907 to disk (but NOT the metadata), by calling the Linux-specific
754 sync_file_range call. If sync_file_range is not available or it 908 sync_file_range call. If sync_file_range is not available or it
758 "IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE", 912 "IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE",
759 "IO::AIO::SYNC_FILE_RANGE_WRITE" and 913 "IO::AIO::SYNC_FILE_RANGE_WRITE" and
760 "IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER": refer to the sync_file_range 914 "IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER": refer to the sync_file_range
761 manpage for details. 915 manpage for details.
762 916
763 aio_pathsync $path, $callback->($status) 917 aio_pathsync $pathname, $callback->($status)
764 This request tries to open, fsync and close the given path. This is 918 This request tries to open, fsync and close the given path. This is
765 a composite request intended to sync directories after directory 919 a composite request intended to sync directories after directory
766 operations (E.g. rename). This might not work on all operating 920 operations (E.g. rename). This might not work on all operating
767 systems or have any specific effect, but usually it makes sure that 921 systems or have any specific effect, but usually it makes sure that
768 directory changes get written to disc. It works for anything that 922 directory changes get written to disc. It works for anything that
795 949
796 It touches (reads or writes) all memory pages in the specified range 950 It touches (reads or writes) all memory pages in the specified range
797 inside the scalar. All caveats and parameters are the same as for 951 inside the scalar. All caveats and parameters are the same as for
798 "aio_msync", above, except for flags, which must be either 0 (which 952 "aio_msync", above, except for flags, which must be either 0 (which
799 reads all pages and ensures they are instantiated) or 953 reads all pages and ensures they are instantiated) or
800 "IO::AIO::MT_MODIFY", which modifies the memory page s(by reading 954 "IO::AIO::MT_MODIFY", which modifies the memory pages (by reading
801 and writing an octet from it, which dirties the page). 955 and writing an octet from it, which dirties the page).
802 956
803 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) 957 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
804 This is a rather advanced IO::AIO call, which works best on 958 This is a rather advanced IO::AIO call, which works best on
805 mmap(2)ed scalars. 959 mmap(2)ed scalars.
837 991
838 Example: asynchronously lock all current and future pages into 992 Example: asynchronously lock all current and future pages into
839 memory. 993 memory.
840 994
841 aio_mlockall IO::AIO::MCL_FUTURE; 995 aio_mlockall IO::AIO::MCL_FUTURE;
996
997 aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
998 Queries the extents of the given file (by calling the Linux "FIEMAP"
999 ioctl, see <http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for
1000 details). If the ioctl is not available on your OS, then this
1001 request will fail with "ENOSYS".
1002
1003 $start is the starting offset to query extents for, $length is the
1004 size of the range to query - if it is "undef", then the whole file
1005 will be queried.
1006
1007 $flags is a combination of flags ("IO::AIO::FIEMAP_FLAG_SYNC" or
1008 "IO::AIO::FIEMAP_FLAG_XATTR" - "IO::AIO::FIEMAP_FLAGS_COMPAT" is
1009 also exported), and is normally 0 or "IO::AIO::FIEMAP_FLAG_SYNC" to
1010 query the data portion.
1011
1012 $count is the maximum number of extent records to return. If it is
1013 "undef", then IO::AIO queries all extents of the range. As a very
1014 special case, if it is 0, then the callback receives the number of
1015 extents instead of the extents themselves (which is unreliable, see
1016 below).
1017
1018 If an error occurs, the callback receives no arguments. The special
1019 "errno" value "IO::AIO::EBADR" is available to test for flag errors.
1020
1021 Otherwise, the callback receives an array reference with extent
1022 structures. Each extent structure is an array reference itself, with
1023 the following members:
1024
1025 [$logical, $physical, $length, $flags]
1026
1027 Flags is any combination of the following flag values (typically
1028 either 0 or "IO::AIO::FIEMAP_EXTENT_LAST" (1)):
1029
1030 "IO::AIO::FIEMAP_EXTENT_LAST", "IO::AIO::FIEMAP_EXTENT_UNKNOWN",
1031 "IO::AIO::FIEMAP_EXTENT_DELALLOC", "IO::AIO::FIEMAP_EXTENT_ENCODED",
1032 "IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED",
1033 "IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED",
1034 "IO::AIO::FIEMAP_EXTENT_DATA_INLINE",
1035 "IO::AIO::FIEMAP_EXTENT_DATA_TAIL",
1036 "IO::AIO::FIEMAP_EXTENT_UNWRITTEN", "IO::AIO::FIEMAP_EXTENT_MERGED"
1037 or "IO::AIO::FIEMAP_EXTENT_SHARED".
1038
1039 At the time of this writing (Linux 3.2), this requets is unreliable
1040 unless $count is "undef", as the kernel has all sorts of bugs
1041 preventing it to return all extents of a range for files with large
1042 number of extents. The code works around all these issues if $count
1043 is undef.
842 1044
843 aio_group $callback->(...) 1045 aio_group $callback->(...)
844 This is a very special aio request: Instead of doing something, it 1046 This is a very special aio request: Instead of doing something, it
845 is a container for other aio requests, which is useful if you want 1047 is a container for other aio requests, which is useful if you want
846 to bundle many requests into a single, composite, request with a 1048 to bundle many requests into a single, composite, request with a
880 While it is theoretically handy to have simple I/O scheduling 1082 While it is theoretically handy to have simple I/O scheduling
881 requests like sleep and file handle readable/writable, the overhead 1083 requests like sleep and file handle readable/writable, the overhead
882 this creates is immense (it blocks a thread for a long time) so do 1084 this creates is immense (it blocks a thread for a long time) so do
883 not use this function except to put your application under 1085 not use this function except to put your application under
884 artificial I/O pressure. 1086 artificial I/O pressure.
1087
1088 IO::AIO::WD - multiple working directories
1089 Your process only has one current working directory, which is used by
1090 all threads. This makes it hard to use relative paths (some other
1091 component could call "chdir" at any time, and it is hard to control when
1092 the path will be used by IO::AIO).
1093
1094 One solution for this is to always use absolute paths. This usually
1095 works, but can be quite slow (the kernel has to walk the whole path on
1096 every access), and can also be a hassle to implement.
1097
1098 Newer POSIX systems have a number of functions (openat, fdopendir,
1099 futimensat and so on) that make it possible to specify working
1100 directories per operation.
1101
1102 For portability, and because the clowns who "designed", or shall I
1103 write, perpetrated this new interface were obviously half-drunk, this
1104 abstraction cannot be perfect, though.
1105
1106 IO::AIO allows you to convert directory paths into a so-called
1107 IO::AIO::WD object. This object stores the canonicalised, absolute
1108 version of the path, and on systems that allow it, also a directory file
1109 descriptor.
1110
1111 Everywhere where a pathname is accepted by IO::AIO (e.g. in "aio_stat"
1112 or "aio_unlink"), one can specify an array reference with an IO::AIO::WD
1113 object and a pathname instead (or the IO::AIO::WD object alone, which
1114 gets interpreted as "[$wd, "."]"). If the pathname is absolute, the
1115 IO::AIO::WD object is ignored, otherwise the pathname is resolved
1116 relative to that IO::AIO::WD object.
1117
1118 For example, to get a wd object for /etc and then stat passwd inside,
1119 you would write:
1120
1121 aio_wd "/etc", sub {
1122 my $etcdir = shift;
1123
1124 # although $etcdir can be undef on error, there is generally no reason
1125 # to check for errors here, as aio_stat will fail with ENOENT
1126 # when $etcdir is undef.
1127
1128 aio_stat [$etcdir, "passwd"], sub {
1129 # yay
1130 };
1131 };
1132
1133 That "aio_wd" is a request and not a normal function shows that creating
1134 an IO::AIO::WD object is itself a potentially blocking operation, which
1135 is why it is done asynchronously.
1136
1137 To stat the directory obtained with "aio_wd" above, one could write
1138 either of the following three request calls:
1139
1140 aio_lstat "/etc" , sub { ... # pathname as normal string
1141 aio_lstat [$wd, "."], sub { ... # "." relative to $wd (i.e. $wd itself)
1142 aio_lstat $wd , sub { ... # shorthand for the previous
1143
1144 As with normal pathnames, IO::AIO keeps a copy of the working directory
1145 object and the pathname string, so you could write the following without
1146 causing any issues due to $path getting reused:
1147
1148 my $path = [$wd, undef];
1149
1150 for my $name (qw(abc def ghi)) {
1151 $path->[1] = $name;
1152 aio_stat $path, sub {
1153 # ...
1154 };
1155 }
1156
1157 There are some caveats: when directories get renamed (or deleted), the
1158 pathname string doesn't change, so will point to the new directory (or
1159 nowhere at all), while the directory fd, if available on the system,
1160 will still point to the original directory. Most functions accepting a
1161 pathname will use the directory fd on newer systems, and the string on
1162 older systems. Some functions (such as realpath) will always rely on the
1163 string form of the pathname.
1164
1165 So this functionality is mainly useful to get some protection against
1166 "chdir", to easily get an absolute path out of a relative path for
1167 future reference, and to speed up doing many operations in the same
1168 directory (e.g. when stat'ing all files in a directory).
1169
1170 The following functions implement this working directory abstraction:
1171
1172 aio_wd $pathname, $callback->($wd)
1173 Asynchonously canonicalise the given pathname and convert it to an
1174 IO::AIO::WD object representing it. If possible and supported on the
1175 system, also open a directory fd to speed up pathname resolution
1176 relative to this working directory.
1177
1178 If something goes wrong, then "undef" is passwd to the callback
1179 instead of a working directory object and $! is set appropriately.
1180 Since passing "undef" as working directory component of a pathname
1181 fails the request with "ENOENT", there is often no need for error
1182 checking in the "aio_wd" callback, as future requests using the
1183 value will fail in the expected way.
1184
1185 IO::AIO::CWD
1186 This is a compiletime constant (object) that represents the process
1187 current working directory.
1188
1189 Specifying this object as working directory object for a pathname is
1190 as if the pathname would be specified directly, without a directory
1191 object. For example, these calls are functionally identical:
1192
1193 aio_stat "somefile", sub { ... };
1194 aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
1195
1196 To recover the path associated with an IO::AIO::WD object, you can use
1197 "aio_realpath":
1198
1199 aio_realpath $wd, sub {
1200 warn "path is $_[0]\n";
1201 };
1202
1203 Currently, "aio_statvfs" always, and "aio_rename" and "aio_rmdir"
1204 sometimes, fall back to using an absolue path.
885 1205
886 IO::AIO::REQ CLASS 1206 IO::AIO::REQ CLASS
887 All non-aggregate "aio_*" functions return an object of this class when 1207 All non-aggregate "aio_*" functions return an object of this class when
888 called in non-void context. 1208 called in non-void context.
889 1209
989 Sets a feeder/generator on this group: every group can have an 1309 Sets a feeder/generator on this group: every group can have an
990 attached generator that generates requests if idle. The idea behind 1310 attached generator that generates requests if idle. The idea behind
991 this is that, although you could just queue as many requests as you 1311 this is that, although you could just queue as many requests as you
992 want in a group, this might starve other requests for a potentially 1312 want in a group, this might starve other requests for a potentially
993 long time. For example, "aio_scandir" might generate hundreds of 1313 long time. For example, "aio_scandir" might generate hundreds of
994 thousands "aio_stat" requests, delaying any later requests for a 1314 thousands of "aio_stat" requests, delaying any later requests for a
995 long time. 1315 long time.
996 1316
997 To avoid this, and allow incremental generation of requests, you can 1317 To avoid this, and allow incremental generation of requests, you can
998 instead a group and set a feeder on it that generates those 1318 instead a group and set a feeder on it that generates those
999 requests. The feed callback will be called whenever there are few 1319 requests. The feed callback will be called whenever there are few
1041 results. 1361 results.
1042 1362
1043 See "poll_cb" for an example. 1363 See "poll_cb" for an example.
1044 1364
1045 IO::AIO::poll_cb 1365 IO::AIO::poll_cb
1046 Process some outstanding events on the result pipe. You have to call 1366 Process some requests that have reached the result phase (i.e. they
1367 have been executed but the results are not yet reported). You have
1368 to call this "regularly" to finish outstanding requests.
1369
1047 this regularly. Returns 0 if all events could be processed (or there 1370 Returns 0 if all events could be processed (or there were no events
1048 were no events to process), or -1 if it returned earlier for 1371 to process), or -1 if it returned earlier for whatever reason.
1049 whatever reason. Returns immediately when no events are outstanding. 1372 Returns immediately when no events are outstanding. The amount of
1050 The amount of events processed depends on the settings of 1373 events processed depends on the settings of "IO::AIO::max_poll_req",
1051 "IO::AIO::max_poll_req" and "IO::AIO::max_poll_time". 1374 "IO::AIO::max_poll_time" and "IO::AIO::max_outstanding".
1052 1375
1053 If not all requests were processed for whatever reason, the 1376 If not all requests were processed for whatever reason, the poll
1054 filehandle will still be ready when "poll_cb" returns, so normally 1377 file descriptor will still be ready when "poll_cb" returns, so
1055 you don't have to do anything special to have it called later. 1378 normally you don't have to do anything special to have it called
1379 later.
1056 1380
1057 Apart from calling "IO::AIO::poll_cb" when the event filehandle 1381 Apart from calling "IO::AIO::poll_cb" when the event filehandle
1058 becomes ready, it can be beneficial to call this function from loops 1382 becomes ready, it can be beneficial to call this function from loops
1059 which submit a lot of requests, to make sure the results get 1383 which submit a lot of requests, to make sure the results get
1060 processed when they become available and not just when the loop is 1384 processed when they become available and not just when the loop is
1068 Event->io (fd => IO::AIO::poll_fileno, 1392 Event->io (fd => IO::AIO::poll_fileno,
1069 poll => 'r', async => 1, 1393 poll => 'r', async => 1,
1070 cb => \&IO::AIO::poll_cb); 1394 cb => \&IO::AIO::poll_cb);
1071 1395
1072 IO::AIO::poll_wait 1396 IO::AIO::poll_wait
1073 If there are any outstanding requests and none of them in the result 1397 Wait until either at least one request is in the result phase or no
1074 phase, wait till the result filehandle becomes ready for reading 1398 requests are outstanding anymore.
1075 (simply does a "select" on the filehandle. This is useful if you 1399
1076 want to synchronously wait for some requests to finish). 1400 This is useful if you want to synchronously wait for some requests
1401 to become ready, without actually handling them.
1077 1402
1078 See "nreqs" for an example. 1403 See "nreqs" for an example.
1079 1404
1080 IO::AIO::poll 1405 IO::AIO::poll
1081 Waits until some requests have been handled. 1406 Waits until some requests have been handled.
1247 1572
1248 Returns the number of bytes copied, or -1 on error. 1573 Returns the number of bytes copied, or -1 on error.
1249 1574
1250 IO::AIO::fadvise $fh, $offset, $len, $advice 1575 IO::AIO::fadvise $fh, $offset, $len, $advice
1251 Simply calls the "posix_fadvise" function (see its manpage for 1576 Simply calls the "posix_fadvise" function (see its manpage for
1252 details). The following advice constants are avaiable: 1577 details). The following advice constants are available:
1253 "IO::AIO::FADV_NORMAL", "IO::AIO::FADV_SEQUENTIAL", 1578 "IO::AIO::FADV_NORMAL", "IO::AIO::FADV_SEQUENTIAL",
1254 "IO::AIO::FADV_RANDOM", "IO::AIO::FADV_NOREUSE", 1579 "IO::AIO::FADV_RANDOM", "IO::AIO::FADV_NOREUSE",
1255 "IO::AIO::FADV_WILLNEED", "IO::AIO::FADV_DONTNEED". 1580 "IO::AIO::FADV_WILLNEED", "IO::AIO::FADV_DONTNEED".
1256 1581
1257 On systems that do not implement "posix_fadvise", this function 1582 On systems that do not implement "posix_fadvise", this function
1258 returns ENOSYS, otherwise the return value of "posix_fadvise". 1583 returns ENOSYS, otherwise the return value of "posix_fadvise".
1259 1584
1260 IO::AIO::madvise $scalar, $offset, $len, $advice 1585 IO::AIO::madvise $scalar, $offset, $len, $advice
1261 Simply calls the "posix_madvise" function (see its manpage for 1586 Simply calls the "posix_madvise" function (see its manpage for
1262 details). The following advice constants are avaiable: 1587 details). The following advice constants are available:
1263 "IO::AIO::MADV_NORMAL", "IO::AIO::MADV_SEQUENTIAL", 1588 "IO::AIO::MADV_NORMAL", "IO::AIO::MADV_SEQUENTIAL",
1264 "IO::AIO::MADV_RANDOM", "IO::AIO::MADV_WILLNEED", 1589 "IO::AIO::MADV_RANDOM", "IO::AIO::MADV_WILLNEED",
1265 "IO::AIO::MADV_DONTNEED". 1590 "IO::AIO::MADV_DONTNEED".
1266 1591
1267 On systems that do not implement "posix_madvise", this function 1592 On systems that do not implement "posix_madvise", this function
1268 returns ENOSYS, otherwise the return value of "posix_madvise". 1593 returns ENOSYS, otherwise the return value of "posix_madvise".
1269 1594
1270 IO::AIO::mprotect $scalar, $offset, $len, $protect 1595 IO::AIO::mprotect $scalar, $offset, $len, $protect
1271 Simply calls the "mprotect" function on the preferably AIO::mmap'ed 1596 Simply calls the "mprotect" function on the preferably AIO::mmap'ed
1272 $scalar (see its manpage for details). The following protect 1597 $scalar (see its manpage for details). The following protect
1273 constants are avaiable: "IO::AIO::PROT_NONE", "IO::AIO::PROT_READ", 1598 constants are available: "IO::AIO::PROT_NONE", "IO::AIO::PROT_READ",
1274 "IO::AIO::PROT_WRITE", "IO::AIO::PROT_EXEC". 1599 "IO::AIO::PROT_WRITE", "IO::AIO::PROT_EXEC".
1275 1600
1276 On systems that do not implement "mprotect", this function returns 1601 On systems that do not implement "mprotect", this function returns
1277 ENOSYS, otherwise the return value of "mprotect". 1602 ENOSYS, otherwise the return value of "mprotect".
1278 1603
1279 IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset] 1604 IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1280 Memory-maps a file (or anonymous memory range) and attaches it to 1605 Memory-maps a file (or anonymous memory range) and attaches it to
1281 the given $scalar, which will act like a string scalar. 1606 the given $scalar, which will act like a string scalar. Returns true
1607 on success, and false otherwise.
1282 1608
1283 The only operations allowed on the scalar are "substr"/"vec" that 1609 The only operations allowed on the scalar are "substr"/"vec" that
1284 don't change the string length, and most read-only operations such 1610 don't change the string length, and most read-only operations such
1285 as copying it or searching it with regexes and so on. 1611 as copying it or searching it with regexes and so on.
1286 1612
1337 Calls the "munlockall" function. 1663 Calls the "munlockall" function.
1338 1664
1339 On systems that do not implement "munlockall", this function returns 1665 On systems that do not implement "munlockall", this function returns
1340 ENOSYS, otherwise the return value of "munlockall". 1666 ENOSYS, otherwise the return value of "munlockall".
1341 1667
1668 IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
1669 Calls the GNU/Linux splice(2) syscall, if available. If $r_off or
1670 $w_off are "undef", then "NULL" is passed for these, otherwise they
1671 should be the file offset.
1672
1673 $r_fh and $w_fh should not refer to the same file, as splice might
1674 silently corrupt the data in this case.
1675
1676 The following symbol flag values are available:
1677 "IO::AIO::SPLICE_F_MOVE", "IO::AIO::SPLICE_F_NONBLOCK",
1678 "IO::AIO::SPLICE_F_MORE" and "IO::AIO::SPLICE_F_GIFT".
1679
1680 See the splice(2) manpage for details.
1681
1682 IO::AIO::tee $r_fh, $w_fh, $length, $flags
1683 Calls the GNU/Linux tee(2) syscall, see it's manpage and the
1684 description for "IO::AIO::splice" above for details.
1685
1686 $actual_size = IO::AIO::pipesize $r_fh[, $new_size]
1687 Attempts to query or change the pipe buffer size. Obviously works
1688 only on pipes, and currently works only on GNU/Linux systems, and
1689 fails with -1/"ENOSYS" everywhere else. If anybody knows how to
1690 influence pipe buffer size on other systems, drop me a note.
1691
1342EVENT LOOP INTEGRATION 1692EVENT LOOP INTEGRATION
1343 It is recommended to use AnyEvent::AIO to integrate IO::AIO 1693 It is recommended to use AnyEvent::AIO to integrate IO::AIO
1344 automatically into many event loops: 1694 automatically into many event loops:
1345 1695
1346 # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...) 1696 # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
1371 1721
1372 FORK BEHAVIOUR 1722 FORK BEHAVIOUR
1373 Usage of pthreads in a program changes the semantics of fork 1723 Usage of pthreads in a program changes the semantics of fork
1374 considerably. Specifically, only async-safe functions can be called 1724 considerably. Specifically, only async-safe functions can be called
1375 after fork. Perl doesn't know about this, so in general, you cannot call 1725 after fork. Perl doesn't know about this, so in general, you cannot call
1376 fork with defined behaviour in perl. IO::AIO uses pthreads, so this 1726 fork with defined behaviour in perl if pthreads are involved. IO::AIO
1377 applies, but many other extensions and (for inexplicable reasons) perl 1727 uses pthreads, so this applies, but many other extensions and (for
1378 itself often is linked against pthreads, so this limitation applies. 1728 inexplicable reasons) perl itself often is linked against pthreads, so
1729 this limitation applies to quite a lot of perls.
1379 1730
1380 Some operating systems have extensions that allow safe use of fork, and 1731 This module no longer tries to fight your OS, or POSIX. That means
1381 this module should do "the right thing" on those, and tries on others. 1732 IO::AIO only works in the process that loaded it. Forking is fully
1382 At the time of this writing (2011) only GNU/Linux supports these 1733 supported, but using IO::AIO in the child is not.
1383 extensions to POSIX. 1734
1735 You might get around by not *using* IO::AIO before (or after) forking.
1736 You could also try to call the IO::AIO::reinit function in the child:
1737
1738 IO::AIO::reinit
1739 Abandons all current requests and I/O threads and simply
1740 reinitialises all data structures. This is not an operation
1741 supported by any standards, but happens to work on GNU/Linux and
1742 some newer BSD systems.
1743
1744 The only reasonable use for this function is to call it after
1745 forking, if "IO::AIO" was used in the parent. Calling it while
1746 IO::AIO is active in the process will result in undefined behaviour.
1747 Calling it at any time will also result in any undefined (by POSIX)
1748 behaviour.
1384 1749
1385 MEMORY USAGE 1750 MEMORY USAGE
1386 Per-request usage: 1751 Per-request usage:
1387 1752
1388 Each aio request uses - depending on your architecture - around 100-200 1753 Each aio request uses - depending on your architecture - around 100-200

Diff Legend

Removed lines
+ Added lines
< Changed lines
> Changed lines