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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.209 by root, Tue Sep 27 00:41:51 2011 UTC vs.
Revision 1.260 by root, Sun May 1 17:19:39 2016 UTC

68=head2 EXAMPLE 68=head2 EXAMPLE
69 69
70This is a simple example that uses the EV module and loads 70This is a simple example that uses the EV module and loads
71F</etc/passwd> asynchronously: 71F</etc/passwd> asynchronously:
72 72
73 use Fcntl;
74 use EV; 73 use EV;
75 use IO::AIO; 74 use IO::AIO;
76 75
77 # register the IO::AIO callback with EV 76 # register the IO::AIO callback with EV
78 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb; 77 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
95 94
96 # file contents now in $contents 95 # file contents now in $contents
97 print $contents; 96 print $contents;
98 97
99 # exit event loop and program 98 # exit event loop and program
100 EV::unloop; 99 EV::break;
101 }; 100 };
102 }; 101 };
103 102
104 # possibly queue up other requests, or open GUI windows, 103 # possibly queue up other requests, or open GUI windows,
105 # check for sockets etc. etc. 104 # check for sockets etc. etc.
106 105
107 # process events as long as there are some: 106 # process events as long as there are some:
108 EV::loop; 107 EV::run;
109 108
110=head1 REQUEST ANATOMY AND LIFETIME 109=head1 REQUEST ANATOMY AND LIFETIME
111 110
112Every C<aio_*> function creates a request. which is a C data structure not 111Every C<aio_*> function creates a request. which is a C data structure not
113directly visible to Perl. 112directly visible to Perl.
168use common::sense; 167use common::sense;
169 168
170use base 'Exporter'; 169use base 'Exporter';
171 170
172BEGIN { 171BEGIN {
173 our $VERSION = '4.0'; 172 our $VERSION = 4.34;
174 173
175 our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close 174 our @AIO_REQ = qw(aio_sendfile aio_seek aio_read aio_write aio_open aio_close
176 aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx 175 aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx
177 aio_scandir aio_symlink aio_readlink aio_realpath aio_sync 176 aio_scandir aio_symlink aio_readlink aio_realpath aio_fcntl aio_ioctl
178 aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range aio_fallocate 177 aio_sync aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range
179 aio_pathsync aio_readahead 178 aio_pathsync aio_readahead aio_fiemap aio_allocate
180 aio_rename aio_link aio_move aio_copy aio_group 179 aio_rename aio_link aio_move aio_copy aio_group
181 aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown 180 aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
182 aio_chmod aio_utime aio_truncate 181 aio_chmod aio_utime aio_truncate
183 aio_msync aio_mtouch aio_mlock aio_mlockall 182 aio_msync aio_mtouch aio_mlock aio_mlockall
184 aio_statvfs 183 aio_statvfs
202 201
203=head1 FUNCTIONS 202=head1 FUNCTIONS
204 203
205=head2 QUICK OVERVIEW 204=head2 QUICK OVERVIEW
206 205
207This section simply lists the prototypes of the most important functions 206This section simply lists the prototypes most of the functions for
208for quick reference. See the following sections for function-by-function 207quick reference. See the following sections for function-by-function
209documentation. 208documentation.
210 209
211 aio_wd $pathname, $callback->($wd) 210 aio_wd $pathname, $callback->($wd)
212 aio_open $pathname, $flags, $mode, $callback->($fh) 211 aio_open $pathname, $flags, $mode, $callback->($fh)
213 aio_close $fh, $callback->($status) 212 aio_close $fh, $callback->($status)
213 aio_seek $fh,$offset,$whence, $callback->($offs)
214 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 214 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
215 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 215 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
216 aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) 216 aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
217 aio_readahead $fh,$offset,$length, $callback->($retval) 217 aio_readahead $fh,$offset,$length, $callback->($retval)
218 aio_stat $fh_or_path, $callback->($status) 218 aio_stat $fh_or_path, $callback->($status)
219 aio_lstat $fh, $callback->($status) 219 aio_lstat $fh, $callback->($status)
220 aio_statvfs $fh_or_path, $callback->($statvfs) 220 aio_statvfs $fh_or_path, $callback->($statvfs)
221 aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 221 aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
222 aio_chown $fh_or_path, $uid, $gid, $callback->($status) 222 aio_chown $fh_or_path, $uid, $gid, $callback->($status)
223 aio_chmod $fh_or_path, $mode, $callback->($status)
223 aio_truncate $fh_or_path, $offset, $callback->($status) 224 aio_truncate $fh_or_path, $offset, $callback->($status)
224 aio_chmod $fh_or_path, $mode, $callback->($status) 225 aio_allocate $fh, $mode, $offset, $len, $callback->($status)
226 aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
225 aio_unlink $pathname, $callback->($status) 227 aio_unlink $pathname, $callback->($status)
226 aio_mknod $pathname, $mode, $dev, $callback->($status) 228 aio_mknod $pathname, $mode, $dev, $callback->($status)
227 aio_link $srcpath, $dstpath, $callback->($status) 229 aio_link $srcpath, $dstpath, $callback->($status)
228 aio_symlink $srcpath, $dstpath, $callback->($status) 230 aio_symlink $srcpath, $dstpath, $callback->($status)
229 aio_readlink $pathname, $callback->($link) 231 aio_readlink $pathname, $callback->($link)
230 aio_realpath $pathname, $callback->($link) 232 aio_realpath $pathname, $callback->($path)
231 aio_rename $srcpath, $dstpath, $callback->($status) 233 aio_rename $srcpath, $dstpath, $callback->($status)
232 aio_mkdir $pathname, $mode, $callback->($status) 234 aio_mkdir $pathname, $mode, $callback->($status)
233 aio_rmdir $pathname, $callback->($status) 235 aio_rmdir $pathname, $callback->($status)
234 aio_readdir $pathname, $callback->($entries) 236 aio_readdir $pathname, $callback->($entries)
235 aio_readdirx $pathname, $flags, $callback->($entries, $flags) 237 aio_readdirx $pathname, $flags, $callback->($entries, $flags)
236 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST 238 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
237 IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN 239 IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
240 aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
238 aio_load $pathname, $data, $callback->($status) 241 aio_load $pathname, $data, $callback->($status)
239 aio_copy $srcpath, $dstpath, $callback->($status) 242 aio_copy $srcpath, $dstpath, $callback->($status)
240 aio_move $srcpath, $dstpath, $callback->($status) 243 aio_move $srcpath, $dstpath, $callback->($status)
241 aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
242 aio_rmtree $pathname, $callback->($status) 244 aio_rmtree $pathname, $callback->($status)
245 aio_fcntl $fh, $cmd, $arg, $callback->($status)
246 aio_ioctl $fh, $request, $buf, $callback->($status)
243 aio_sync $callback->($status) 247 aio_sync $callback->($status)
244 aio_syncfs $fh, $callback->($status) 248 aio_syncfs $fh, $callback->($status)
245 aio_fsync $fh, $callback->($status) 249 aio_fsync $fh, $callback->($status)
246 aio_fdatasync $fh, $callback->($status) 250 aio_fdatasync $fh, $callback->($status)
247 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status) 251 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
271 IO::AIO::nready 275 IO::AIO::nready
272 IO::AIO::npending 276 IO::AIO::npending
273 277
274 IO::AIO::sendfile $ofh, $ifh, $offset, $count 278 IO::AIO::sendfile $ofh, $ifh, $offset, $count
275 IO::AIO::fadvise $fh, $offset, $len, $advice 279 IO::AIO::fadvise $fh, $offset, $len, $advice
280 IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
281 IO::AIO::munmap $scalar
276 IO::AIO::madvise $scalar, $offset, $length, $advice 282 IO::AIO::madvise $scalar, $offset, $length, $advice
277 IO::AIO::mprotect $scalar, $offset, $length, $protect 283 IO::AIO::mprotect $scalar, $offset, $length, $protect
278 IO::AIO::munlock $scalar, $offset = 0, $length = undef 284 IO::AIO::munlock $scalar, $offset = 0, $length = undef
279 IO::AIO::munlockall 285 IO::AIO::munlockall
280 286
281=head2 AIO REQUEST FUNCTIONS 287=head2 API NOTES
282 288
283All the C<aio_*> calls are more or less thin wrappers around the syscall 289All the C<aio_*> calls are more or less thin wrappers around the syscall
284with the same name (sans C<aio_>). The arguments are similar or identical, 290with the same name (sans C<aio_>). The arguments are similar or identical,
285and they all accept an additional (and optional) C<$callback> argument 291and they all accept an additional (and optional) C<$callback> argument
286which must be a code reference. This code reference will get called with 292which must be a code reference. This code reference will be called after
287the syscall return code (e.g. most syscalls return C<-1> on error, unlike 293the syscall has been executed in an asynchronous fashion. The results
288perl, which usually delivers "false") as its sole argument after the given 294of the request will be passed as arguments to the callback (and, if an
289syscall has been executed asynchronously. 295error occured, in C<$!>) - for most requests the syscall return code (e.g.
296most syscalls return C<-1> on error, unlike perl, which usually delivers
297"false").
298
299Some requests (such as C<aio_readdir>) pass the actual results and
300communicate failures by passing C<undef>.
290 301
291All functions expecting a filehandle keep a copy of the filehandle 302All functions expecting a filehandle keep a copy of the filehandle
292internally until the request has finished. 303internally until the request has finished.
293 304
294All functions return request objects of type L<IO::AIO::REQ> that allow 305All functions return request objects of type L<IO::AIO::REQ> that allow
295further manipulation of those requests while they are in-flight. 306further manipulation of those requests while they are in-flight.
296 307
297The pathnames you pass to these routines I<should> be absolute. The 308The pathnames you pass to these routines I<should> be absolute. The
298reason for this is that at the time the request is being executed, the 309reason for this is that at the time the request is being executed, the
299current working directory could have changed. Alternatively, you can make 310current working directory could have changed. Alternatively, you can
300sure that you never change the current working directory anywhere in 311make sure that you never change the current working directory anywhere
301the program and then use relative paths. Lastly, you can take advantage 312in the program and then use relative paths. You can also take advantage
302of IO::AIOs working directory abstraction - see the description of the 313of IO::AIOs working directory abstraction, that lets you specify paths
314relative to some previously-opened "working directory object" - see the
303C<IO::AIO::WD> class later in this document. 315description of the C<IO::AIO::WD> class later in this document.
304 316
305To encode pathnames as octets, either make sure you either: a) always pass 317To encode pathnames as octets, either make sure you either: a) always pass
306in filenames you got from outside (command line, readdir etc.) without 318in filenames you got from outside (command line, readdir etc.) without
307tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module and encode 319tinkering, b) are in your native filesystem encoding, c) use the Encode
308your pathnames to the locale (or other) encoding in effect in the user 320module and encode your pathnames to the locale (or other) encoding in
309environment, d) use Glib::filename_from_unicode on unicode filenames or e) 321effect in the user environment, d) use Glib::filename_from_unicode on
310use something else to ensure your scalar has the correct contents. 322unicode filenames or e) use something else to ensure your scalar has the
323correct contents.
311 324
312This works, btw. independent of the internal UTF-8 bit, which IO::AIO 325This works, btw. independent of the internal UTF-8 bit, which IO::AIO
313handles correctly whether it is set or not. 326handles correctly whether it is set or not.
327
328=head2 AIO REQUEST FUNCTIONS
314 329
315=over 4 330=over 4
316 331
317=item $prev_pri = aioreq_pri [$pri] 332=item $prev_pri = aioreq_pri [$pri]
318 333
348 363
349 364
350=item aio_open $pathname, $flags, $mode, $callback->($fh) 365=item aio_open $pathname, $flags, $mode, $callback->($fh)
351 366
352Asynchronously open or create a file and call the callback with a newly 367Asynchronously open or create a file and call the callback with a newly
353created filehandle for the file. 368created filehandle for the file (or C<undef> in case of an error).
354 369
355The pathname passed to C<aio_open> must be absolute. See API NOTES, above, 370The pathname passed to C<aio_open> must be absolute. See API NOTES, above,
356for an explanation. 371for an explanation.
357 372
358The C<$flags> argument is a bitmask. See the C<Fcntl> module for a 373The C<$flags> argument is a bitmask. See the C<Fcntl> module for a
381following POSIX and non-POSIX constants are available (missing ones on 396following POSIX and non-POSIX constants are available (missing ones on
382your system are, as usual, C<0>): 397your system are, as usual, C<0>):
383 398
384C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>, 399C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,
385C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>, 400C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,
386C<O_RSYNC>, C<O_SYNC> and C<O_TTY_INIT>. 401C<O_RSYNC>, C<O_SYNC>, C<O_PATH>, C<O_TMPFILE>, and C<O_TTY_INIT>.
387 402
388 403
389=item aio_close $fh, $callback->($status) 404=item aio_close $fh, $callback->($status)
390 405
391Asynchronously close a file and call the callback with the result 406Asynchronously close a file and call the callback with the result
400 415
401Or in other words: the file descriptor will be closed, but it will not be 416Or in other words: the file descriptor will be closed, but it will not be
402free for reuse until the perl filehandle is closed. 417free for reuse until the perl filehandle is closed.
403 418
404=cut 419=cut
420
421=item aio_seek $fh, $offset, $whence, $callback->($offs)
422
423Seeks the filehandle to the new C<$offset>, similarly to perl's
424C<sysseek>. The C<$whence> can use the traditional values (C<0> for
425C<IO::AIO::SEEK_SET>, C<1> for C<IO::AIO::SEEK_CUR> or C<2> for
426C<IO::AIO::SEEK_END>).
427
428The resulting absolute offset will be passed to the callback, or C<-1> in
429case of an error.
430
431In theory, the C<$whence> constants could be different than the
432corresponding values from L<Fcntl>, but perl guarantees they are the same,
433so don't panic.
434
435As a GNU/Linux (and maybe Solaris) extension, also the constants
436C<IO::AIO::SEEK_DATA> and C<IO::AIO::SEEK_HOLE> are available, if they
437could be found. No guarantees about suitability for use in C<aio_seek> or
438Perl's C<sysseek> can be made though, although I would naively assume they
439"just work".
405 440
406=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 441=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
407 442
408=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 443=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
409 444
569 namemax => 255, 604 namemax => 255,
570 frsize => 1024, 605 frsize => 1024,
571 fsid => 1810 606 fsid => 1810
572 } 607 }
573 608
609Here is a (likely partial - send me updates!) list of fsid values used by
610Linux - it is safe to hardcode these when C<$^O> is C<linux>:
611
612 0x0000adf5 adfs
613 0x0000adff affs
614 0x5346414f afs
615 0x09041934 anon-inode filesystem
616 0x00000187 autofs
617 0x42465331 befs
618 0x1badface bfs
619 0x42494e4d binfmt_misc
620 0x9123683e btrfs
621 0x0027e0eb cgroupfs
622 0xff534d42 cifs
623 0x73757245 coda
624 0x012ff7b7 coh
625 0x28cd3d45 cramfs
626 0x453dcd28 cramfs-wend (wrong endianness)
627 0x64626720 debugfs
628 0x00001373 devfs
629 0x00001cd1 devpts
630 0x0000f15f ecryptfs
631 0x00414a53 efs
632 0x0000137d ext
633 0x0000ef53 ext2/ext3/ext4
634 0x0000ef51 ext2
635 0xf2f52010 f2fs
636 0x00004006 fat
637 0x65735546 fuseblk
638 0x65735543 fusectl
639 0x0bad1dea futexfs
640 0x01161970 gfs2
641 0x47504653 gpfs
642 0x00004244 hfs
643 0xf995e849 hpfs
644 0x00c0ffee hostfs
645 0x958458f6 hugetlbfs
646 0x2bad1dea inotifyfs
647 0x00009660 isofs
648 0x000072b6 jffs2
649 0x3153464a jfs
650 0x6b414653 k-afs
651 0x0bd00bd0 lustre
652 0x0000137f minix
653 0x0000138f minix 30 char names
654 0x00002468 minix v2
655 0x00002478 minix v2 30 char names
656 0x00004d5a minix v3
657 0x19800202 mqueue
658 0x00004d44 msdos
659 0x0000564c novell
660 0x00006969 nfs
661 0x6e667364 nfsd
662 0x00003434 nilfs
663 0x5346544e ntfs
664 0x00009fa1 openprom
665 0x7461636F ocfs2
666 0x00009fa0 proc
667 0x6165676c pstorefs
668 0x0000002f qnx4
669 0x68191122 qnx6
670 0x858458f6 ramfs
671 0x52654973 reiserfs
672 0x00007275 romfs
673 0x67596969 rpc_pipefs
674 0x73636673 securityfs
675 0xf97cff8c selinux
676 0x0000517b smb
677 0x534f434b sockfs
678 0x73717368 squashfs
679 0x62656572 sysfs
680 0x012ff7b6 sysv2
681 0x012ff7b5 sysv4
682 0x01021994 tmpfs
683 0x15013346 udf
684 0x00011954 ufs
685 0x54190100 ufs byteswapped
686 0x00009fa2 usbdevfs
687 0x01021997 v9fs
688 0xa501fcf5 vxfs
689 0xabba1974 xenfs
690 0x012ff7b4 xenix
691 0x58465342 xfs
692 0x012fd16d xia
574 693
575=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 694=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
576 695
577Works like perl's C<utime> function (including the special case of $atime 696Works like perl's C<utime> function (including the special case of $atime
578and $mtime being undef). Fractional times are supported if the underlying 697and $mtime being undef). Fractional times are supported if the underlying
606=item aio_truncate $fh_or_path, $offset, $callback->($status) 725=item aio_truncate $fh_or_path, $offset, $callback->($status)
607 726
608Works like truncate(2) or ftruncate(2). 727Works like truncate(2) or ftruncate(2).
609 728
610 729
730=item aio_allocate $fh, $mode, $offset, $len, $callback->($status)
731
732Allocates or frees disk space according to the C<$mode> argument. See the
733linux C<fallocate> documentation for details.
734
735C<$mode> is usually C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE> to allocate
736space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE | IO::AIO::FALLOC_FL_KEEP_SIZE>,
737to deallocate a file range.
738
739IO::AIO also supports C<FALLOC_FL_COLLAPSE_RANGE>, to remove a range
740(without leaving a hole) and C<FALLOC_FL_ZERO_RANGE>, to zero a range (see
741your L<fallocate(2)> manpage).
742
743The file system block size used by C<fallocate> is presumably the
744C<f_bsize> returned by C<statvfs>.
745
746If C<fallocate> isn't available or cannot be emulated (currently no
747emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>.
748
749
611=item aio_chmod $fh_or_path, $mode, $callback->($status) 750=item aio_chmod $fh_or_path, $mode, $callback->($status)
612 751
613Works like perl's C<chmod> function. 752Works like perl's C<chmod> function.
614 753
615 754
652 791
653 792
654=item aio_realpath $pathname, $callback->($path) 793=item aio_realpath $pathname, $callback->($path)
655 794
656Asynchronously make the path absolute and resolve any symlinks in 795Asynchronously make the path absolute and resolve any symlinks in
657C<$path>. The resulting path only consists of directories (Same as 796C<$path>. The resulting path only consists of directories (same as
658L<Cwd::realpath>). 797L<Cwd::realpath>).
659 798
660This request can be used to get the absolute path of the current working 799This request can be used to get the absolute path of the current working
661directory by passing it a path of F<.> (a single dot). 800directory by passing it a path of F<.> (a single dot).
662 801
663 802
664=item aio_rename $srcpath, $dstpath, $callback->($status) 803=item aio_rename $srcpath, $dstpath, $callback->($status)
665 804
666Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as 805Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
667rename(2) and call the callback with the result code. 806rename(2) and call the callback with the result code.
807
808On systems that support the AIO::WD working directory abstraction
809natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead
810of failing, C<rename> is called on the absolute path of C<$wd>.
668 811
669 812
670=item aio_mkdir $pathname, $mode, $callback->($status) 813=item aio_mkdir $pathname, $mode, $callback->($status)
671 814
672Asynchronously mkdir (create) a directory and call the callback with 815Asynchronously mkdir (create) a directory and call the callback with
676 819
677=item aio_rmdir $pathname, $callback->($status) 820=item aio_rmdir $pathname, $callback->($status)
678 821
679Asynchronously rmdir (delete) a directory and call the callback with the 822Asynchronously rmdir (delete) a directory and call the callback with the
680result code. 823result code.
824
825On systems that support the AIO::WD working directory abstraction
826natively, the case C<[$wd, "."]> is specialcased - instead of failing,
827C<rmdir> is called on the absolute path of C<$wd>.
681 828
682 829
683=item aio_readdir $pathname, $callback->($entries) 830=item aio_readdir $pathname, $callback->($entries)
684 831
685Unlike the POSIX call of the same name, C<aio_readdir> reads an entire 832Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
966 1113
967 my $grp = aio_group $cb; 1114 my $grp = aio_group $cb;
968 1115
969 $maxreq = 4 if $maxreq <= 0; 1116 $maxreq = 4 if $maxreq <= 0;
970 1117
971 # stat once 1118 # get a wd object
972 aioreq_pri $pri; 1119 aioreq_pri $pri;
973 add $grp aio_stat $path, sub { 1120 add $grp aio_wd $path, sub {
1121 $_[0]
974 return $grp->result () if $_[0]; 1122 or return $grp->result ();
975 my $now = time;
976 my $hash1 = join ":", (stat _)[0,1,3,7,9];
977 1123
978 # read the directory entries 1124 my $wd = [shift, "."];
1125
1126 # stat once
979 aioreq_pri $pri; 1127 aioreq_pri $pri;
980 add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub { 1128 add $grp aio_stat $wd, sub {
981 my $entries = shift
982 or return $grp->result (); 1129 return $grp->result () if $_[0];
1130 my $now = time;
1131 my $hash1 = join ":", (stat _)[0,1,3,7,9];
983 1132
984 # stat the dir another time 1133 # read the directory entries
985 aioreq_pri $pri; 1134 aioreq_pri $pri;
1135 add $grp aio_readdirx $wd, READDIR_DIRS_FIRST, sub {
1136 my $entries = shift
1137 or return $grp->result ();
1138
1139 # stat the dir another time
1140 aioreq_pri $pri;
986 add $grp aio_stat $path, sub { 1141 add $grp aio_stat $wd, sub {
987 my $hash2 = join ":", (stat _)[0,1,3,7,9]; 1142 my $hash2 = join ":", (stat _)[0,1,3,7,9];
988 1143
989 my $ndirs; 1144 my $ndirs;
990 1145
991 # take the slow route if anything looks fishy 1146 # take the slow route if anything looks fishy
992 if ($hash1 ne $hash2 or (stat _)[9] == $now) { 1147 if ($hash1 ne $hash2 or (stat _)[9] == $now) {
993 $ndirs = -1; 1148 $ndirs = -1;
994 } else { 1149 } else {
995 # if nlink == 2, we are finished 1150 # if nlink == 2, we are finished
996 # for non-posix-fs's, we rely on nlink < 2 1151 # for non-posix-fs's, we rely on nlink < 2
997 $ndirs = (stat _)[3] - 2 1152 $ndirs = (stat _)[3] - 2
998 or return $grp->result ([], $entries); 1153 or return $grp->result ([], $entries);
999 } 1154 }
1000 1155
1001 my (@dirs, @nondirs); 1156 my (@dirs, @nondirs);
1002 1157
1003 my $statgrp = add $grp aio_group sub { 1158 my $statgrp = add $grp aio_group sub {
1004 $grp->result (\@dirs, \@nondirs); 1159 $grp->result (\@dirs, \@nondirs);
1005 }; 1160 };
1006 1161
1007 limit $statgrp $maxreq; 1162 limit $statgrp $maxreq;
1008 feed $statgrp sub { 1163 feed $statgrp sub {
1009 return unless @$entries; 1164 return unless @$entries;
1010 my $entry = shift @$entries; 1165 my $entry = shift @$entries;
1011 1166
1012 aioreq_pri $pri; 1167 aioreq_pri $pri;
1168 $wd->[1] = "$entry/.";
1013 add $statgrp aio_stat "$path/$entry/.", sub { 1169 add $statgrp aio_stat $wd, sub {
1014 if ($_[0] < 0) { 1170 if ($_[0] < 0) {
1015 push @nondirs, $entry; 1171 push @nondirs, $entry;
1016 } else { 1172 } else {
1017 # need to check for real directory 1173 # need to check for real directory
1018 aioreq_pri $pri; 1174 aioreq_pri $pri;
1175 $wd->[1] = $entry;
1019 add $statgrp aio_lstat "$path/$entry", sub { 1176 add $statgrp aio_lstat $wd, sub {
1020 if (-d _) { 1177 if (-d _) {
1021 push @dirs, $entry; 1178 push @dirs, $entry;
1022 1179
1023 unless (--$ndirs) { 1180 unless (--$ndirs) {
1024 push @nondirs, @$entries; 1181 push @nondirs, @$entries;
1025 feed $statgrp; 1182 feed $statgrp;
1183 }
1184 } else {
1185 push @nondirs, $entry;
1026 } 1186 }
1027 } else {
1028 push @nondirs, $entry;
1029 } 1187 }
1030 } 1188 }
1031 } 1189 };
1032 }; 1190 };
1033 }; 1191 };
1034 }; 1192 };
1035 }; 1193 };
1036 }; 1194 };
1039} 1197}
1040 1198
1041=item aio_rmtree $pathname, $callback->($status) 1199=item aio_rmtree $pathname, $callback->($status)
1042 1200
1043Delete a directory tree starting (and including) C<$path>, return the 1201Delete a directory tree starting (and including) C<$path>, return the
1044status of the final C<rmdir> only. This is a composite request that 1202status of the final C<rmdir> only. This is a composite request that
1045uses C<aio_scandir> to recurse into and rmdir directories, and unlink 1203uses C<aio_scandir> to recurse into and rmdir directories, and unlink
1046everything else. 1204everything else.
1047 1205
1048=cut 1206=cut
1049 1207
1070 add $grp $dirgrp; 1228 add $grp $dirgrp;
1071 }; 1229 };
1072 1230
1073 $grp 1231 $grp
1074} 1232}
1233
1234=item aio_fcntl $fh, $cmd, $arg, $callback->($status)
1235
1236=item aio_ioctl $fh, $request, $buf, $callback->($status)
1237
1238These work just like the C<fcntl> and C<ioctl> built-in functions, except
1239they execute asynchronously and pass the return value to the callback.
1240
1241Both calls can be used for a lot of things, some of which make more sense
1242to run asynchronously in their own thread, while some others make less
1243sense. For example, calls that block waiting for external events, such
1244as locking, will also lock down an I/O thread while it is waiting, which
1245can deadlock the whole I/O system. At the same time, there might be no
1246alternative to using a thread to wait.
1247
1248So in general, you should only use these calls for things that do
1249(filesystem) I/O, not for things that wait for other events (network,
1250other processes), although if you are careful and know what you are doing,
1251you still can.
1075 1252
1076=item aio_sync $callback->($status) 1253=item aio_sync $callback->($status)
1077 1254
1078Asynchronously call sync and call the callback when finished. 1255Asynchronously call sync and call the callback when finished.
1079 1256
1169 1346
1170This is a rather advanced IO::AIO call, which works best on mmap(2)ed 1347This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1171scalars. 1348scalars.
1172 1349
1173It touches (reads or writes) all memory pages in the specified 1350It touches (reads or writes) all memory pages in the specified
1174range inside the scalar. All caveats and parameters are the same 1351range inside the scalar. All caveats and parameters are the same
1175as for C<aio_msync>, above, except for flags, which must be either 1352as for C<aio_msync>, above, except for flags, which must be either
1176C<0> (which reads all pages and ensures they are instantiated) or 1353C<0> (which reads all pages and ensures they are instantiated) or
1177C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and 1354C<IO::AIO::MT_MODIFY>, which modifies the memory pages (by reading and
1178writing an octet from it, which dirties the page). 1355writing an octet from it, which dirties the page).
1179 1356
1180=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) 1357=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
1181 1358
1182This is a rather advanced IO::AIO call, which works best on mmap(2)ed 1359This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1213documented under L<MISCELLANEOUS FUNCTIONS>. 1390documented under L<MISCELLANEOUS FUNCTIONS>.
1214 1391
1215Example: asynchronously lock all current and future pages into memory. 1392Example: asynchronously lock all current and future pages into memory.
1216 1393
1217 aio_mlockall IO::AIO::MCL_FUTURE; 1394 aio_mlockall IO::AIO::MCL_FUTURE;
1395
1396=item aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
1397
1398Queries the extents of the given file (by calling the Linux C<FIEMAP>
1399ioctl, see L<http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for details). If
1400the ioctl is not available on your OS, then this request will fail with
1401C<ENOSYS>.
1402
1403C<$start> is the starting offset to query extents for, C<$length> is the
1404size of the range to query - if it is C<undef>, then the whole file will
1405be queried.
1406
1407C<$flags> is a combination of flags (C<IO::AIO::FIEMAP_FLAG_SYNC> or
1408C<IO::AIO::FIEMAP_FLAG_XATTR> - C<IO::AIO::FIEMAP_FLAGS_COMPAT> is also
1409exported), and is normally C<0> or C<IO::AIO::FIEMAP_FLAG_SYNC> to query
1410the data portion.
1411
1412C<$count> is the maximum number of extent records to return. If it is
1413C<undef>, then IO::AIO queries all extents of the range. As a very special
1414case, if it is C<0>, then the callback receives the number of extents
1415instead of the extents themselves (which is unreliable, see below).
1416
1417If an error occurs, the callback receives no arguments. The special
1418C<errno> value C<IO::AIO::EBADR> is available to test for flag errors.
1419
1420Otherwise, the callback receives an array reference with extent
1421structures. Each extent structure is an array reference itself, with the
1422following members:
1423
1424 [$logical, $physical, $length, $flags]
1425
1426Flags is any combination of the following flag values (typically either C<0>
1427or C<IO::AIO::FIEMAP_EXTENT_LAST> (1)):
1428
1429C<IO::AIO::FIEMAP_EXTENT_LAST>, C<IO::AIO::FIEMAP_EXTENT_UNKNOWN>,
1430C<IO::AIO::FIEMAP_EXTENT_DELALLOC>, C<IO::AIO::FIEMAP_EXTENT_ENCODED>,
1431C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
1432C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
1433C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
1434C<IO::AIO::FIEMAP_EXTENT_SHARED>.
1435
1436At the time of this writing (Linux 3.2), this requets is unreliable unless
1437C<$count> is C<undef>, as the kernel has all sorts of bugs preventing
1438it to return all extents of a range for files with large number of
1439extents. The code works around all these issues if C<$count> is undef.
1218 1440
1219=item aio_group $callback->(...) 1441=item aio_group $callback->(...)
1220 1442
1221This is a very special aio request: Instead of doing something, it is a 1443This is a very special aio request: Instead of doing something, it is a
1222container for other aio requests, which is useful if you want to bundle 1444container for other aio requests, which is useful if you want to bundle
1286object. This object stores the canonicalised, absolute version of the 1508object. This object stores the canonicalised, absolute version of the
1287path, and on systems that allow it, also a directory file descriptor. 1509path, and on systems that allow it, also a directory file descriptor.
1288 1510
1289Everywhere where a pathname is accepted by IO::AIO (e.g. in C<aio_stat> 1511Everywhere where a pathname is accepted by IO::AIO (e.g. in C<aio_stat>
1290or C<aio_unlink>), one can specify an array reference with an IO::AIO::WD 1512or C<aio_unlink>), one can specify an array reference with an IO::AIO::WD
1291object and a pathname instead. If the pathname is absolute, the 1513object and a pathname instead (or the IO::AIO::WD object alone, which
1514gets interpreted as C<[$wd, "."]>). If the pathname is absolute, the
1292IO::AIO::WD objetc is ignored, otherwise the pathname is resolved relative 1515IO::AIO::WD object is ignored, otherwise the pathname is resolved relative
1293to that IO::AIO::WD object. 1516to that IO::AIO::WD object.
1294 1517
1295For example, to get a wd object for F</etc> and then stat F<passwd> 1518For example, to get a wd object for F</etc> and then stat F<passwd>
1296inside, you would write: 1519inside, you would write:
1297 1520
1305 aio_stat [$etcdir, "passwd"], sub { 1528 aio_stat [$etcdir, "passwd"], sub {
1306 # yay 1529 # yay
1307 }; 1530 };
1308 }; 1531 };
1309 1532
1533The fact that C<aio_wd> is a request and not a normal function shows that
1310This shows that creating an IO::AIO::WD object is itself a potentially 1534creating an IO::AIO::WD object is itself a potentially blocking operation,
1311blocking operation, which is why it is done asynchronously. 1535which is why it is done asynchronously.
1536
1537To stat the directory obtained with C<aio_wd> above, one could write
1538either of the following three request calls:
1539
1540 aio_lstat "/etc" , sub { ... # pathname as normal string
1541 aio_lstat [$wd, "."], sub { ... # "." relative to $wd (i.e. $wd itself)
1542 aio_lstat $wd , sub { ... # shorthand for the previous
1312 1543
1313As with normal pathnames, IO::AIO keeps a copy of the working directory 1544As with normal pathnames, IO::AIO keeps a copy of the working directory
1314object and the pathname string, so you could write the following without 1545object and the pathname string, so you could write the following without
1315causing any issues due to C<$path> getting reused: 1546causing any issues due to C<$path> getting reused:
1316 1547
1329will still point to the original directory. Most functions accepting a 1560will still point to the original directory. Most functions accepting a
1330pathname will use the directory fd on newer systems, and the string on 1561pathname will use the directory fd on newer systems, and the string on
1331older systems. Some functions (such as realpath) will always rely on the 1562older systems. Some functions (such as realpath) will always rely on the
1332string form of the pathname. 1563string form of the pathname.
1333 1564
1334So this fucntionality is mainly useful to get some protection against 1565So this functionality is mainly useful to get some protection against
1335C<chdir>, to easily get an absolute path out of a relative path for future 1566C<chdir>, to easily get an absolute path out of a relative path for future
1336reference, and to speed up doing many operations in the same directory 1567reference, and to speed up doing many operations in the same directory
1337(e.g. when stat'ing all files in a directory). 1568(e.g. when stat'ing all files in a directory).
1338 1569
1339The following functions implement this working directory abstraction: 1570The following functions implement this working directory abstraction:
1352passing C<undef> as working directory component of a pathname fails the 1583passing C<undef> as working directory component of a pathname fails the
1353request with C<ENOENT>, there is often no need for error checking in the 1584request with C<ENOENT>, there is often no need for error checking in the
1354C<aio_wd> callback, as future requests using the value will fail in the 1585C<aio_wd> callback, as future requests using the value will fail in the
1355expected way. 1586expected way.
1356 1587
1357If this call isn't available because your OS lacks it or it couldn't be
1358detected, it will be emulated by calling C<fsync> instead.
1359
1360=item IO::AIO::CWD 1588=item IO::AIO::CWD
1361 1589
1362This is a compiletime constant (object) that represents the process 1590This is a compiletime constant (object) that represents the process
1363current working directory. 1591current working directory.
1364 1592
1365Specifying this object as working directory object for a pathname is as 1593Specifying this object as working directory object for a pathname is as if
1366if the pathname would be specified directly, without a directory object, 1594the pathname would be specified directly, without a directory object. For
1367e.g., these calls are functionally identical: 1595example, these calls are functionally identical:
1368 1596
1369 aio_stat "somefile", sub { ... }; 1597 aio_stat "somefile", sub { ... };
1370 aio_stat [IO::AIO::CWD, "somefile"], sub { ... }; 1598 aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
1371 1599
1372=back 1600=back
1373 1601
1602To recover the path associated with an IO::AIO::WD object, you can use
1603C<aio_realpath>:
1604
1605 aio_realpath $wd, sub {
1606 warn "path is $_[0]\n";
1607 };
1608
1609Currently, C<aio_statvfs> always, and C<aio_rename> and C<aio_rmdir>
1610sometimes, fall back to using an absolue path.
1374 1611
1375=head2 IO::AIO::REQ CLASS 1612=head2 IO::AIO::REQ CLASS
1376 1613
1377All non-aggregate C<aio_*> functions return an object of this class when 1614All non-aggregate C<aio_*> functions return an object of this class when
1378called in non-void context. 1615called in non-void context.
1496 1733
1497Sets a feeder/generator on this group: every group can have an attached 1734Sets a feeder/generator on this group: every group can have an attached
1498generator that generates requests if idle. The idea behind this is that, 1735generator that generates requests if idle. The idea behind this is that,
1499although you could just queue as many requests as you want in a group, 1736although you could just queue as many requests as you want in a group,
1500this might starve other requests for a potentially long time. For example, 1737this might starve other requests for a potentially long time. For example,
1501C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests, 1738C<aio_scandir> might generate hundreds of thousands of C<aio_stat>
1502delaying any later requests for a long time. 1739requests, delaying any later requests for a long time.
1503 1740
1504To avoid this, and allow incremental generation of requests, you can 1741To avoid this, and allow incremental generation of requests, you can
1505instead a group and set a feeder on it that generates those requests. The 1742instead a group and set a feeder on it that generates those requests. The
1506feed callback will be called whenever there are few enough (see C<limit>, 1743feed callback will be called whenever there are few enough (see C<limit>,
1507below) requests active in the group itself and is expected to queue more 1744below) requests active in the group itself and is expected to queue more
1556 1793
1557See C<poll_cb> for an example. 1794See C<poll_cb> for an example.
1558 1795
1559=item IO::AIO::poll_cb 1796=item IO::AIO::poll_cb
1560 1797
1561Process some outstanding events on the result pipe. You have to call 1798Process some requests that have reached the result phase (i.e. they have
1799been executed but the results are not yet reported). You have to call
1800this "regularly" to finish outstanding requests.
1801
1562this regularly. Returns C<0> if all events could be processed (or there 1802Returns C<0> if all events could be processed (or there were no
1563were no events to process), or C<-1> if it returned earlier for whatever 1803events to process), or C<-1> if it returned earlier for whatever
1564reason. Returns immediately when no events are outstanding. The amount of 1804reason. Returns immediately when no events are outstanding. The amount
1565events processed depends on the settings of C<IO::AIO::max_poll_req> and 1805of events processed depends on the settings of C<IO::AIO::max_poll_req>,
1566C<IO::AIO::max_poll_time>. 1806C<IO::AIO::max_poll_time> and C<IO::AIO::max_outstanding>.
1567 1807
1568If not all requests were processed for whatever reason, the filehandle 1808If not all requests were processed for whatever reason, the poll file
1569will still be ready when C<poll_cb> returns, so normally you don't have to 1809descriptor will still be ready when C<poll_cb> returns, so normally you
1570do anything special to have it called later. 1810don't have to do anything special to have it called later.
1571 1811
1572Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes 1812Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
1573ready, it can be beneficial to call this function from loops which submit 1813ready, it can be beneficial to call this function from loops which submit
1574a lot of requests, to make sure the results get processed when they become 1814a lot of requests, to make sure the results get processed when they become
1575available and not just when the loop is finished and the event loop takes 1815available and not just when the loop is finished and the event loop takes
1584 poll => 'r', async => 1, 1824 poll => 'r', async => 1,
1585 cb => \&IO::AIO::poll_cb); 1825 cb => \&IO::AIO::poll_cb);
1586 1826
1587=item IO::AIO::poll_wait 1827=item IO::AIO::poll_wait
1588 1828
1589If there are any outstanding requests and none of them in the result 1829Wait until either at least one request is in the result phase or no
1590phase, wait till the result filehandle becomes ready for reading (simply 1830requests are outstanding anymore.
1591does a C<select> on the filehandle. This is useful if you want to 1831
1592synchronously wait for some requests to finish). 1832This is useful if you want to synchronously wait for some requests to
1833become ready, without actually handling them.
1593 1834
1594See C<nreqs> for an example. 1835See C<nreqs> for an example.
1595 1836
1596=item IO::AIO::poll 1837=item IO::AIO::poll
1597 1838
1718 1959
1719This is a very bad function to use in interactive programs because it 1960This is a very bad function to use in interactive programs because it
1720blocks, and a bad way to reduce concurrency because it is inexact: Better 1961blocks, and a bad way to reduce concurrency because it is inexact: Better
1721use an C<aio_group> together with a feed callback. 1962use an C<aio_group> together with a feed callback.
1722 1963
1723It's main use is in scripts without an event loop - when you want to stat 1964Its main use is in scripts without an event loop - when you want to stat
1724a lot of files, you can write somehting like this: 1965a lot of files, you can write somehting like this:
1725 1966
1726 IO::AIO::max_outstanding 32; 1967 IO::AIO::max_outstanding 32;
1727 1968
1728 for my $path (...) { 1969 for my $path (...) {
1768 2009
1769=back 2010=back
1770 2011
1771=head3 MISCELLANEOUS FUNCTIONS 2012=head3 MISCELLANEOUS FUNCTIONS
1772 2013
1773IO::AIO implements some functions that might be useful, but are not 2014IO::AIO implements some functions that are useful when you want to use
1774asynchronous. 2015some "Advanced I/O" function not available to in Perl, without going the
2016"Asynchronous I/O" route. Many of these have an asynchronous C<aio_*>
2017counterpart.
1775 2018
1776=over 4 2019=over 4
1777 2020
1778=item IO::AIO::sendfile $ofh, $ifh, $offset, $count 2021=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1779 2022
1816ENOSYS, otherwise the return value of C<mprotect>. 2059ENOSYS, otherwise the return value of C<mprotect>.
1817 2060
1818=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset] 2061=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1819 2062
1820Memory-maps a file (or anonymous memory range) and attaches it to the 2063Memory-maps a file (or anonymous memory range) and attaches it to the
1821given C<$scalar>, which will act like a string scalar. 2064given C<$scalar>, which will act like a string scalar. Returns true on
2065success, and false otherwise.
1822 2066
1823The only operations allowed on the scalar are C<substr>/C<vec> that don't 2067The only operations allowed on the scalar are C<substr>/C<vec> that don't
1824change the string length, and most read-only operations such as copying it 2068change the string length, and most read-only operations such as copying it
1825or searching it with regexes and so on. 2069or searching it with regexes and so on.
1826 2070
1837filesize. 2081filesize.
1838 2082
1839C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>, 2083C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
1840C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>, 2084C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
1841 2085
1842C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or 2086C<$flags> can be a combination of
1843C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when 2087C<IO::AIO::MAP_SHARED> or
1844not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS> 2088C<IO::AIO::MAP_PRIVATE>,
2089or a number of system-specific flags (when not available, the are C<0>):
1845(which is set to C<MAP_ANON> if your system only provides this 2090C<IO::AIO::MAP_ANONYMOUS> (which is set to C<MAP_ANON> if your system only provides this constant),
1846constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>, 2091C<IO::AIO::MAP_LOCKED>,
1847C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or 2092C<IO::AIO::MAP_NORESERVE>,
2093C<IO::AIO::MAP_POPULATE>,
1848C<IO::AIO::MAP_NONBLOCK> 2094C<IO::AIO::MAP_NONBLOCK>,
2095C<IO::AIO::MAP_FIXED>,
2096C<IO::AIO::MAP_GROWSDOWN>,
2097C<IO::AIO::MAP_32BIT>,
2098C<IO::AIO::MAP_HUGETLB> or
2099C<IO::AIO::MAP_STACK>.
1849 2100
1850If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed. 2101If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
1851 2102
1852C<$offset> is the offset from the start of the file - it generally must be 2103C<$offset> is the offset from the start of the file - it generally must be
1853a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>. 2104a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
1878 2129
1879Calls the C<munlockall> function. 2130Calls the C<munlockall> function.
1880 2131
1881On systems that do not implement C<munlockall>, this function returns 2132On systems that do not implement C<munlockall>, this function returns
1882ENOSYS, otherwise the return value of C<munlockall>. 2133ENOSYS, otherwise the return value of C<munlockall>.
2134
2135=item IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
2136
2137Calls the GNU/Linux C<splice(2)> syscall, if available. If C<$r_off> or
2138C<$w_off> are C<undef>, then C<NULL> is passed for these, otherwise they
2139should be the file offset.
2140
2141C<$r_fh> and C<$w_fh> should not refer to the same file, as splice might
2142silently corrupt the data in this case.
2143
2144The following symbol flag values are available: C<IO::AIO::SPLICE_F_MOVE>,
2145C<IO::AIO::SPLICE_F_NONBLOCK>, C<IO::AIO::SPLICE_F_MORE> and
2146C<IO::AIO::SPLICE_F_GIFT>.
2147
2148See the C<splice(2)> manpage for details.
2149
2150=item IO::AIO::tee $r_fh, $w_fh, $length, $flags
2151
2152Calls the GNU/Linux C<tee(2)> syscall, see its manpage and the
2153description for C<IO::AIO::splice> above for details.
2154
2155=item $actual_size = IO::AIO::pipesize $r_fh[, $new_size]
2156
2157Attempts to query or change the pipe buffer size. Obviously works only
2158on pipes, and currently works only on GNU/Linux systems, and fails with
2159C<-1>/C<ENOSYS> everywhere else. If anybody knows how to influence pipe buffer
2160size on other systems, drop me a note.
2161
2162=item ($rfh, $wfh) = IO::AIO::pipe2 [$flags]
2163
2164This is a direct interface to the Linux L<pipe2(2)> system call. If
2165C<$flags> is missing or C<0>, then this should be the same as a call to
2166perl's built-in C<pipe> function and create a new pipe, and works on
2167systems that lack the pipe2 syscall. On win32, this case invokes C<_pipe
2168(..., 4096, O_BINARY)>.
2169
2170If C<$flags> is non-zero, it tries to invoke the pipe2 system call with
2171the given flags (Linux 2.6.27, glibc 2.9).
2172
2173On success, the read and write file handles are returned.
2174
2175On error, nothing will be returned. If the pipe2 syscall is missing and
2176C<$flags> is non-zero, fails with C<ENOSYS>.
2177
2178Please refer to L<pipe2(2)> for more info on the C<$flags>, but at the
2179time of this writing, C<IO::AIO::O_CLOEXEC>, C<IO::AIO::O_NONBLOCK> and
2180C<IO::AIO::O_DIRECT> (Linux 3.4, for packet-based pipes) were supported.
1883 2181
1884=back 2182=back
1885 2183
1886=cut 2184=cut
1887 2185

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