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Revision 1.225 by root, Tue Apr 10 05:01:33 2012 UTC vs.
Revision 1.299 by root, Fri Dec 28 12:09:50 2018 UTC

1=head1 NAME 1=head1 NAME
2 2
3IO::AIO - Asynchronous Input/Output 3IO::AIO - Asynchronous/Advanced Input/Output
4 4
5=head1 SYNOPSIS 5=head1 SYNOPSIS
6 6
7 use IO::AIO; 7 use IO::AIO;
8 8
… …
58not well-supported or restricted (GNU/Linux doesn't allow them on normal 58not well-supported or restricted (GNU/Linux doesn't allow them on normal
59files currently, for example), and they would only support aio_read and 59files currently, for example), and they would only support aio_read and
60aio_write, so the remaining functionality would have to be implemented 60aio_write, so the remaining functionality would have to be implemented
61using threads anyway. 61using threads anyway.
62 62
63In addition to asynchronous I/O, this module also exports some rather
64arcane interfaces, such as C<madvise> or linux's C<splice> system call,
65which is why the C<A> in C<AIO> can also mean I<advanced>.
66
63Although the module will work in the presence of other (Perl-) threads, 67Although the module will work in the presence of other (Perl-) threads,
64it is currently not reentrant in any way, so use appropriate locking 68it is currently not reentrant in any way, so use appropriate locking
65yourself, always call C<poll_cb> from within the same thread, or never 69yourself, always call C<poll_cb> from within the same thread, or never
66call C<poll_cb> (or other C<aio_> functions) recursively. 70call C<poll_cb> (or other C<aio_> functions) recursively.
67 71
68=head2 EXAMPLE 72=head2 EXAMPLE
69 73
70This is a simple example that uses the EV module and loads 74This is a simple example that uses the EV module and loads
71F</etc/passwd> asynchronously: 75F</etc/passwd> asynchronously:
72 76
73 use Fcntl;
74 use EV; 77 use EV;
75 use IO::AIO; 78 use IO::AIO;
76 79
77 # register the IO::AIO callback with EV 80 # register the IO::AIO callback with EV
78 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb; 81 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
… …
95 98
96 # file contents now in $contents 99 # file contents now in $contents
97 print $contents; 100 print $contents;
98 101
99 # exit event loop and program 102 # exit event loop and program
100 EV::unloop; 103 EV::break;
101 }; 104 };
102 }; 105 };
103 106
104 # possibly queue up other requests, or open GUI windows, 107 # possibly queue up other requests, or open GUI windows,
105 # check for sockets etc. etc. 108 # check for sockets etc. etc.
106 109
107 # process events as long as there are some: 110 # process events as long as there are some:
108 EV::loop; 111 EV::run;
109 112
110=head1 REQUEST ANATOMY AND LIFETIME 113=head1 REQUEST ANATOMY AND LIFETIME
111 114
112Every C<aio_*> function creates a request. which is a C data structure not 115Every C<aio_*> function creates a request. which is a C data structure not
113directly visible to Perl. 116directly visible to Perl.
… …
168use common::sense; 171use common::sense;
169 172
170use base 'Exporter'; 173use base 'Exporter';
171 174
172BEGIN { 175BEGIN {
173 our $VERSION = '4.15'; 176 our $VERSION = 4.7;
174 177
175 our @AIO_REQ = qw(aio_sendfile aio_seek aio_read aio_write aio_open aio_close 178 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 179 aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx
177 aio_scandir aio_symlink aio_readlink aio_realpath aio_sync 180 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 181 aio_sync aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range
179 aio_pathsync aio_readahead aio_fiemap 182 aio_pathsync aio_readahead aio_fiemap aio_allocate
180 aio_rename aio_link aio_move aio_copy aio_group 183 aio_rename aio_rename2 aio_link aio_move aio_copy aio_group
181 aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown 184 aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
182 aio_chmod aio_utime aio_truncate 185 aio_chmod aio_utime aio_truncate
183 aio_msync aio_mtouch aio_mlock aio_mlockall 186 aio_msync aio_mtouch aio_mlock aio_mlockall
184 aio_statvfs 187 aio_statvfs
188 aio_slurp
185 aio_wd); 189 aio_wd);
186 190
187 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice)); 191 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
188 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush 192 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
189 min_parallel max_parallel max_idle idle_timeout 193 min_parallel max_parallel max_idle idle_timeout
190 nreqs nready npending nthreads 194 nreqs nready npending nthreads
191 max_poll_time max_poll_reqs 195 max_poll_time max_poll_reqs
192 sendfile fadvise madvise 196 sendfile fadvise madvise
193 mmap munmap munlock munlockall); 197 mmap munmap mremap munlock munlockall);
194 198
195 push @AIO_REQ, qw(aio_busy); # not exported 199 push @AIO_REQ, qw(aio_busy); # not exported
196 200
197 @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; 201 @IO::AIO::GRP::ISA = 'IO::AIO::REQ';
198 202
… …
202 206
203=head1 FUNCTIONS 207=head1 FUNCTIONS
204 208
205=head2 QUICK OVERVIEW 209=head2 QUICK OVERVIEW
206 210
207This section simply lists the prototypes of the most important functions 211This section simply lists the prototypes most of the functions for
208for quick reference. See the following sections for function-by-function 212quick reference. See the following sections for function-by-function
209documentation. 213documentation.
210 214
211 aio_wd $pathname, $callback->($wd) 215 aio_wd $pathname, $callback->($wd)
212 aio_open $pathname, $flags, $mode, $callback->($fh) 216 aio_open $pathname, $flags, $mode, $callback->($fh)
213 aio_close $fh, $callback->($status) 217 aio_close $fh, $callback->($status)
… …
221 aio_statvfs $fh_or_path, $callback->($statvfs) 225 aio_statvfs $fh_or_path, $callback->($statvfs)
222 aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 226 aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
223 aio_chown $fh_or_path, $uid, $gid, $callback->($status) 227 aio_chown $fh_or_path, $uid, $gid, $callback->($status)
224 aio_chmod $fh_or_path, $mode, $callback->($status) 228 aio_chmod $fh_or_path, $mode, $callback->($status)
225 aio_truncate $fh_or_path, $offset, $callback->($status) 229 aio_truncate $fh_or_path, $offset, $callback->($status)
230 aio_allocate $fh, $mode, $offset, $len, $callback->($status)
231 aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
226 aio_unlink $pathname, $callback->($status) 232 aio_unlink $pathname, $callback->($status)
227 aio_mknod $pathname, $mode, $dev, $callback->($status) 233 aio_mknod $pathname, $mode, $dev, $callback->($status)
228 aio_link $srcpath, $dstpath, $callback->($status) 234 aio_link $srcpath, $dstpath, $callback->($status)
229 aio_symlink $srcpath, $dstpath, $callback->($status) 235 aio_symlink $srcpath, $dstpath, $callback->($status)
230 aio_readlink $pathname, $callback->($link) 236 aio_readlink $pathname, $callback->($link)
231 aio_realpath $pathname, $callback->($link) 237 aio_realpath $pathname, $callback->($path)
232 aio_rename $srcpath, $dstpath, $callback->($status) 238 aio_rename $srcpath, $dstpath, $callback->($status)
239 aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
233 aio_mkdir $pathname, $mode, $callback->($status) 240 aio_mkdir $pathname, $mode, $callback->($status)
234 aio_rmdir $pathname, $callback->($status) 241 aio_rmdir $pathname, $callback->($status)
235 aio_readdir $pathname, $callback->($entries) 242 aio_readdir $pathname, $callback->($entries)
236 aio_readdirx $pathname, $flags, $callback->($entries, $flags) 243 aio_readdirx $pathname, $flags, $callback->($entries, $flags)
237 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST 244 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
… …
239 aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs) 246 aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
240 aio_load $pathname, $data, $callback->($status) 247 aio_load $pathname, $data, $callback->($status)
241 aio_copy $srcpath, $dstpath, $callback->($status) 248 aio_copy $srcpath, $dstpath, $callback->($status)
242 aio_move $srcpath, $dstpath, $callback->($status) 249 aio_move $srcpath, $dstpath, $callback->($status)
243 aio_rmtree $pathname, $callback->($status) 250 aio_rmtree $pathname, $callback->($status)
251 aio_fcntl $fh, $cmd, $arg, $callback->($status)
252 aio_ioctl $fh, $request, $buf, $callback->($status)
244 aio_sync $callback->($status) 253 aio_sync $callback->($status)
245 aio_syncfs $fh, $callback->($status) 254 aio_syncfs $fh, $callback->($status)
246 aio_fsync $fh, $callback->($status) 255 aio_fsync $fh, $callback->($status)
247 aio_fdatasync $fh, $callback->($status) 256 aio_fdatasync $fh, $callback->($status)
248 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status) 257 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
249 aio_pathsync $pathname, $callback->($status) 258 aio_pathsync $pathname, $callback->($status)
250 aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 259 aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
251 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 260 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
252 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) 261 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
253 aio_mlockall $flags, $callback->($status) 262 aio_mlockall $flags, $callback->($status)
254 aio_group $callback->(...) 263 aio_group $callback->(...)
255 aio_nop $callback->() 264 aio_nop $callback->()
… …
269 IO::AIO::idle_timeout $seconds 278 IO::AIO::idle_timeout $seconds
270 IO::AIO::max_outstanding $maxreqs 279 IO::AIO::max_outstanding $maxreqs
271 IO::AIO::nreqs 280 IO::AIO::nreqs
272 IO::AIO::nready 281 IO::AIO::nready
273 IO::AIO::npending 282 IO::AIO::npending
283 $nfd = IO::AIO::get_fdlimit [EXPERIMENTAL]
284 IO::AIO::min_fdlimit $nfd [EXPERIMENTAL]
274 285
275 IO::AIO::sendfile $ofh, $ifh, $offset, $count 286 IO::AIO::sendfile $ofh, $ifh, $offset, $count
276 IO::AIO::fadvise $fh, $offset, $len, $advice 287 IO::AIO::fadvise $fh, $offset, $len, $advice
288 IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
289 IO::AIO::munmap $scalar
290 IO::AIO::mremap $scalar, $new_length, $flags[, $new_address]
277 IO::AIO::madvise $scalar, $offset, $length, $advice 291 IO::AIO::madvise $scalar, $offset, $length, $advice
278 IO::AIO::mprotect $scalar, $offset, $length, $protect 292 IO::AIO::mprotect $scalar, $offset, $length, $protect
279 IO::AIO::munlock $scalar, $offset = 0, $length = undef 293 IO::AIO::munlock $scalar, $offset = 0, $length = undef
280 IO::AIO::munlockall 294 IO::AIO::munlockall
281 295
… …
358 372
359 373
360=item aio_open $pathname, $flags, $mode, $callback->($fh) 374=item aio_open $pathname, $flags, $mode, $callback->($fh)
361 375
362Asynchronously open or create a file and call the callback with a newly 376Asynchronously open or create a file and call the callback with a newly
363created filehandle for the file. 377created filehandle for the file (or C<undef> in case of an error).
364 378
365The pathname passed to C<aio_open> must be absolute. See API NOTES, above, 379The pathname passed to C<aio_open> must be absolute. See API NOTES, above,
366for an explanation. 380for an explanation.
367 381
368The C<$flags> argument is a bitmask. See the C<Fcntl> module for a 382The C<$flags> argument is a bitmask. See the C<Fcntl> module for a
… …
391following POSIX and non-POSIX constants are available (missing ones on 405following POSIX and non-POSIX constants are available (missing ones on
392your system are, as usual, C<0>): 406your system are, as usual, C<0>):
393 407
394C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>, 408C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,
395C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>, 409C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,
396C<O_RSYNC>, C<O_SYNC> and C<O_TTY_INIT>. 410C<O_RSYNC>, C<O_SYNC>, C<O_PATH>, C<O_TMPFILE>, C<O_TTY_INIT> and C<O_ACCMODE>.
397 411
398 412
399=item aio_close $fh, $callback->($status) 413=item aio_close $fh, $callback->($status)
400 414
401Asynchronously close a file and call the callback with the result 415Asynchronously close a file and call the callback with the result
… …
436=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 450=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
437 451
438=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 452=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
439 453
440Reads or writes C<$length> bytes from or to the specified C<$fh> and 454Reads or writes C<$length> bytes from or to the specified C<$fh> and
441C<$offset> into the scalar given by C<$data> and offset C<$dataoffset> 455C<$offset> into the scalar given by C<$data> and offset C<$dataoffset> and
442and calls the callback without the actual number of bytes read (or -1 on 456calls the callback with the actual number of bytes transferred (or -1 on
443error, just like the syscall). 457error, just like the syscall).
444 458
445C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to 459C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
446offset plus the actual number of bytes read. 460offset plus the actual number of bytes read.
447 461
… …
505As native sendfile syscalls (as practically any non-POSIX interface hacked 519As native sendfile syscalls (as practically any non-POSIX interface hacked
506together in a hurry to improve benchmark numbers) tend to be rather buggy 520together in a hurry to improve benchmark numbers) tend to be rather buggy
507on many systems, this implementation tries to work around some known bugs 521on many systems, this implementation tries to work around some known bugs
508in Linux and FreeBSD kernels (probably others, too), but that might fail, 522in Linux and FreeBSD kernels (probably others, too), but that might fail,
509so you really really should check the return value of C<aio_sendfile> - 523so you really really should check the return value of C<aio_sendfile> -
510fewre bytes than expected might have been transferred. 524fewer bytes than expected might have been transferred.
511 525
512 526
513=item aio_readahead $fh,$offset,$length, $callback->($retval) 527=item aio_readahead $fh,$offset,$length, $callback->($retval)
514 528
515C<aio_readahead> populates the page cache with data from a file so that 529C<aio_readahead> populates the page cache with data from a file so that
… …
519whole pages, so that offset is effectively rounded down to a page boundary 533whole pages, so that offset is effectively rounded down to a page boundary
520and bytes are read up to the next page boundary greater than or equal to 534and bytes are read up to the next page boundary greater than or equal to
521(off-set+length). C<aio_readahead> does not read beyond the end of the 535(off-set+length). C<aio_readahead> does not read beyond the end of the
522file. The current file offset of the file is left unchanged. 536file. The current file offset of the file is left unchanged.
523 537
524If that syscall doesn't exist (likely if your OS isn't Linux) it will be 538If that syscall doesn't exist (likely if your kernel isn't Linux) it will
525emulated by simply reading the data, which would have a similar effect. 539be emulated by simply reading the data, which would have a similar effect.
526 540
527 541
528=item aio_stat $fh_or_path, $callback->($status) 542=item aio_stat $fh_or_path, $callback->($status)
529 543
530=item aio_lstat $fh, $callback->($status) 544=item aio_lstat $fh, $callback->($status)
531 545
532Works like perl's C<stat> or C<lstat> in void context. The callback will 546Works almost exactly like perl's C<stat> or C<lstat> in void context. The
533be called after the stat and the results will be available using C<stat _> 547callback will be called after the stat and the results will be available
534or C<-s _> etc... 548using C<stat _> or C<-s _> and other tests (with the exception of C<-B>
549and C<-T>).
535 550
536The pathname passed to C<aio_stat> must be absolute. See API NOTES, above, 551The pathname passed to C<aio_stat> must be absolute. See API NOTES, above,
537for an explanation. 552for an explanation.
538 553
539Currently, the stats are always 64-bit-stats, i.e. instead of returning an 554Currently, the stats are always 64-bit-stats, i.e. instead of returning an
… …
546behaviour). 561behaviour).
547 562
548C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>, 563C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>,
549C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>, 564C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>,
550C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>. 565C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>.
566
567To access higher resolution stat timestamps, see L<SUBSECOND STAT TIME
568ACCESS>.
551 569
552Example: Print the length of F</etc/passwd>: 570Example: Print the length of F</etc/passwd>:
553 571
554 aio_stat "/etc/passwd", sub { 572 aio_stat "/etc/passwd", sub {
555 $_[0] and die "stat failed: $!"; 573 $_[0] and die "stat failed: $!";
… …
599 namemax => 255, 617 namemax => 255,
600 frsize => 1024, 618 frsize => 1024,
601 fsid => 1810 619 fsid => 1810
602 } 620 }
603 621
604
605=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 622=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
606 623
607Works like perl's C<utime> function (including the special case of $atime 624Works like perl's C<utime> function (including the special case of $atime
608and $mtime being undef). Fractional times are supported if the underlying 625and $mtime being undef). Fractional times are supported if the underlying
609syscalls support them. 626syscalls support them.
610 627
611When called with a pathname, uses utimes(2) if available, otherwise 628When called with a pathname, uses utimensat(2) or utimes(2) if available,
612utime(2). If called on a file descriptor, uses futimes(2) if available, 629otherwise utime(2). If called on a file descriptor, uses futimens(2)
613otherwise returns ENOSYS, so this is not portable. 630or futimes(2) if available, otherwise returns ENOSYS, so this is not
631portable.
614 632
615Examples: 633Examples:
616 634
617 # set atime and mtime to current time (basically touch(1)): 635 # set atime and mtime to current time (basically touch(1)):
618 aio_utime "path", undef, undef; 636 aio_utime "path", undef, undef;
… …
636=item aio_truncate $fh_or_path, $offset, $callback->($status) 654=item aio_truncate $fh_or_path, $offset, $callback->($status)
637 655
638Works like truncate(2) or ftruncate(2). 656Works like truncate(2) or ftruncate(2).
639 657
640 658
659=item aio_allocate $fh, $mode, $offset, $len, $callback->($status)
660
661Allocates or frees disk space according to the C<$mode> argument. See the
662linux C<fallocate> documentation for details.
663
664C<$mode> is usually C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE> to allocate
665space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE | IO::AIO::FALLOC_FL_KEEP_SIZE>,
666to deallocate a file range.
667
668IO::AIO also supports C<FALLOC_FL_COLLAPSE_RANGE>, to remove a range
669(without leaving a hole), C<FALLOC_FL_ZERO_RANGE>, to zero a range,
670C<FALLOC_FL_INSERT_RANGE> to insert a range and C<FALLOC_FL_UNSHARE_RANGE>
671to unshare shared blocks (see your L<fallocate(2)> manpage).
672
673The file system block size used by C<fallocate> is presumably the
674C<f_bsize> returned by C<statvfs>, but different filesystems and filetypes
675can dictate other limitations.
676
677If C<fallocate> isn't available or cannot be emulated (currently no
678emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>.
679
680
641=item aio_chmod $fh_or_path, $mode, $callback->($status) 681=item aio_chmod $fh_or_path, $mode, $callback->($status)
642 682
643Works like perl's C<chmod> function. 683Works like perl's C<chmod> function.
644 684
645 685
… …
682 722
683 723
684=item aio_realpath $pathname, $callback->($path) 724=item aio_realpath $pathname, $callback->($path)
685 725
686Asynchronously make the path absolute and resolve any symlinks in 726Asynchronously make the path absolute and resolve any symlinks in
687C<$path>. The resulting path only consists of directories (Same as 727C<$path>. The resulting path only consists of directories (same as
688L<Cwd::realpath>). 728L<Cwd::realpath>).
689 729
690This request can be used to get the absolute path of the current working 730This request can be used to get the absolute path of the current working
691directory by passing it a path of F<.> (a single dot). 731directory by passing it a path of F<.> (a single dot).
692 732
693 733
694=item aio_rename $srcpath, $dstpath, $callback->($status) 734=item aio_rename $srcpath, $dstpath, $callback->($status)
695 735
696Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as 736Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
697rename(2) and call the callback with the result code. 737rename(2) and call the callback with the result code.
738
739On systems that support the AIO::WD working directory abstraction
740natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead
741of failing, C<rename> is called on the absolute path of C<$wd>.
742
743
744=item aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
745
746Basically a version of C<aio_rename> with an additional C<$flags>
747argument. Calling this with C<$flags=0> is the same as calling
748C<aio_rename>.
749
750Non-zero flags are currently only supported on GNU/Linux systems that
751support renameat2. Other systems fail with C<ENOSYS> in this case.
752
753The following constants are available (missing ones are, as usual C<0>),
754see renameat2(2) for details:
755
756C<IO::AIO::RENAME_NOREPLACE>, C<IO::AIO::RENAME_EXCHANGE>
757and C<IO::AIO::RENAME_WHITEOUT>.
698 758
699 759
700=item aio_mkdir $pathname, $mode, $callback->($status) 760=item aio_mkdir $pathname, $mode, $callback->($status)
701 761
702Asynchronously mkdir (create) a directory and call the callback with 762Asynchronously mkdir (create) a directory and call the callback with
… …
707=item aio_rmdir $pathname, $callback->($status) 767=item aio_rmdir $pathname, $callback->($status)
708 768
709Asynchronously rmdir (delete) a directory and call the callback with the 769Asynchronously rmdir (delete) a directory and call the callback with the
710result code. 770result code.
711 771
772On systems that support the AIO::WD working directory abstraction
773natively, the case C<[$wd, "."]> is specialcased - instead of failing,
774C<rmdir> is called on the absolute path of C<$wd>.
775
712 776
713=item aio_readdir $pathname, $callback->($entries) 777=item aio_readdir $pathname, $callback->($entries)
714 778
715Unlike the POSIX call of the same name, C<aio_readdir> reads an entire 779Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
716directory (i.e. opendir + readdir + closedir). The entries will not be 780directory (i.e. opendir + readdir + closedir). The entries will not be
… …
731 795
732=over 4 796=over 4
733 797
734=item IO::AIO::READDIR_DENTS 798=item IO::AIO::READDIR_DENTS
735 799
736When this flag is off, then the callback gets an arrayref consisting of 800Normally the callback gets an arrayref consisting of names only (as
737names only (as with C<aio_readdir>), otherwise it gets an arrayref with 801with C<aio_readdir>). If this flag is set, then the callback gets an
738C<[$name, $type, $inode]> arrayrefs, each describing a single directory 802arrayref with C<[$name, $type, $inode]> arrayrefs, each describing a
739entry in more detail. 803single directory entry in more detail:
740 804
741C<$name> is the name of the entry. 805C<$name> is the name of the entry.
742 806
743C<$type> is one of the C<IO::AIO::DT_xxx> constants: 807C<$type> is one of the C<IO::AIO::DT_xxx> constants:
744 808
745C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>, 809C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
746C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>, 810C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
747C<IO::AIO::DT_WHT>. 811C<IO::AIO::DT_WHT>.
748 812
749C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to 813C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need
750know, you have to run stat yourself. Also, for speed reasons, the C<$type> 814to know, you have to run stat yourself. Also, for speed/memory reasons,
751scalars are read-only: you can not modify them. 815the C<$type> scalars are read-only: you must not modify them.
752 816
753C<$inode> is the inode number (which might not be exact on systems with 64 817C<$inode> is the inode number (which might not be exact on systems with 64
754bit inode numbers and 32 bit perls). This field has unspecified content on 818bit inode numbers and 32 bit perls). This field has unspecified content on
755systems that do not deliver the inode information. 819systems that do not deliver the inode information.
756 820
… …
767short names are tried first. 831short names are tried first.
768 832
769=item IO::AIO::READDIR_STAT_ORDER 833=item IO::AIO::READDIR_STAT_ORDER
770 834
771When this flag is set, then the names will be returned in an order 835When this flag is set, then the names will be returned in an order
772suitable for stat()'ing each one. That is, when you plan to stat() 836suitable for stat()'ing each one. That is, when you plan to stat() most or
773all files in the given directory, then the returned order will likely 837all files in the given directory, then the returned order will likely be
774be fastest. 838faster.
775 839
776If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then 840If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified,
777the likely dirs come first, resulting in a less optimal stat order. 841then the likely dirs come first, resulting in a less optimal stat order
842for stat'ing all entries, but likely a more optimal order for finding
843subdirectories.
778 844
779=item IO::AIO::READDIR_FOUND_UNKNOWN 845=item IO::AIO::READDIR_FOUND_UNKNOWN
780 846
781This flag should not be set when calling C<aio_readdirx>. Instead, it 847This flag should not be set when calling C<aio_readdirx>. Instead, it
782is being set by C<aio_readdirx>, when any of the C<$type>'s found were 848is being set by C<aio_readdirx>, when any of the C<$type>'s found were
… …
784C<$type>'s are known, which can be used to speed up some algorithms. 850C<$type>'s are known, which can be used to speed up some algorithms.
785 851
786=back 852=back
787 853
788 854
855=item aio_slurp $pathname, $offset, $length, $data, $callback->($status)
856
857Opens, reads and closes the given file. The data is put into C<$data>,
858which is resized as required.
859
860If C<$offset> is negative, then it is counted from the end of the file.
861
862If C<$length> is zero, then the remaining length of the file is
863used. Also, in this case, the same limitations to modifying C<$data> apply
864as when IO::AIO::mmap is used, i.e. it must only be modified in-place
865with C<substr>. If the size of the file is known, specifying a non-zero
866C<$length> results in a performance advantage.
867
868This request is similar to the older C<aio_load> request, but since it is
869a single request, it might be more efficient to use.
870
871Example: load F</etc/passwd> into C<$passwd>.
872
873 my $passwd;
874 aio_slurp "/etc/passwd", 0, 0, $passwd, sub {
875 $_[0] >= 0
876 or die "/etc/passwd: $!\n";
877
878 printf "/etc/passwd is %d bytes long, and contains:\n", length $passwd;
879 print $passwd;
880 };
881 IO::AIO::flush;
882
883
789=item aio_load $pathname, $data, $callback->($status) 884=item aio_load $pathname, $data, $callback->($status)
790 885
791This is a composite request that tries to fully load the given file into 886This is a composite request that tries to fully load the given file into
792memory. Status is the same as with aio_read. 887memory. Status is the same as with aio_read.
888
889Using C<aio_slurp> might be more efficient, as it is a single request.
793 890
794=cut 891=cut
795 892
796sub aio_load($$;$) { 893sub aio_load($$;$) {
797 my ($path, undef, $cb) = @_; 894 my ($path, undef, $cb) = @_;
… …
817=item aio_copy $srcpath, $dstpath, $callback->($status) 914=item aio_copy $srcpath, $dstpath, $callback->($status)
818 915
819Try to copy the I<file> (directories not supported as either source or 916Try to copy the I<file> (directories not supported as either source or
820destination) from C<$srcpath> to C<$dstpath> and call the callback with 917destination) from C<$srcpath> to C<$dstpath> and call the callback with
821a status of C<0> (ok) or C<-1> (error, see C<$!>). 918a status of C<0> (ok) or C<-1> (error, see C<$!>).
919
920Existing destination files will be truncated.
822 921
823This is a composite request that creates the destination file with 922This is a composite request that creates the destination file with
824mode 0200 and copies the contents of the source file into it using 923mode 0200 and copies the contents of the source file into it using
825C<aio_sendfile>, followed by restoring atime, mtime, access mode and 924C<aio_sendfile>, followed by restoring atime, mtime, access mode and
826uid/gid, in that order. 925uid/gid, in that order.
… …
936Scans a directory (similar to C<aio_readdir>) but additionally tries to 1035Scans a directory (similar to C<aio_readdir>) but additionally tries to
937efficiently separate the entries of directory C<$path> into two sets of 1036efficiently separate the entries of directory C<$path> into two sets of
938names, directories you can recurse into (directories), and ones you cannot 1037names, directories you can recurse into (directories), and ones you cannot
939recurse into (everything else, including symlinks to directories). 1038recurse into (everything else, including symlinks to directories).
940 1039
941C<aio_scandir> is a composite request that creates of many sub requests_ 1040C<aio_scandir> is a composite request that generates many sub requests.
942C<$maxreq> specifies the maximum number of outstanding aio requests that 1041C<$maxreq> specifies the maximum number of outstanding aio requests that
943this function generates. If it is C<< <= 0 >>, then a suitable default 1042this function generates. If it is C<< <= 0 >>, then a suitable default
944will be chosen (currently 4). 1043will be chosen (currently 4).
945 1044
946On error, the callback is called without arguments, otherwise it receives 1045On error, the callback is called without arguments, otherwise it receives
… …
1010 aioreq_pri $pri; 1109 aioreq_pri $pri;
1011 add $grp aio_stat $wd, sub { 1110 add $grp aio_stat $wd, sub {
1012 return $grp->result () if $_[0]; 1111 return $grp->result () if $_[0];
1013 my $now = time; 1112 my $now = time;
1014 my $hash1 = join ":", (stat _)[0,1,3,7,9]; 1113 my $hash1 = join ":", (stat _)[0,1,3,7,9];
1114 my $rdxflags = READDIR_DIRS_FIRST;
1115
1116 if ((stat _)[3] < 2) {
1117 # at least one non-POSIX filesystem exists
1118 # that returns useful DT_type values: btrfs,
1119 # so optimise for this here by requesting dents
1120 $rdxflags |= READDIR_DENTS;
1121 }
1015 1122
1016 # read the directory entries 1123 # read the directory entries
1017 aioreq_pri $pri; 1124 aioreq_pri $pri;
1018 add $grp aio_readdirx $wd, READDIR_DIRS_FIRST, sub { 1125 add $grp aio_readdirx $wd, $rdxflags, sub {
1019 my $entries = shift 1126 my ($entries, $flags) = @_
1020 or return $grp->result (); 1127 or return $grp->result ();
1128
1129 if ($rdxflags & READDIR_DENTS) {
1130 # if we requested type values, see if we can use them directly.
1131
1132 # if there were any DT_UNKNOWN entries then we assume we
1133 # don't know. alternatively, we could assume that if we get
1134 # one DT_DIR, then all directories are indeed marked with
1135 # DT_DIR, but this seems not required for btrfs, and this
1136 # is basically the "btrfs can't get it's act together" code
1137 # branch.
1138 unless ($flags & READDIR_FOUND_UNKNOWN) {
1139 # now we have valid DT_ information for all entries,
1140 # so use it as an optimisation without further stat's.
1141 # they must also all be at the beginning of @$entries
1142 # by now.
1143
1144 my $dirs;
1145
1146 if (@$entries) {
1147 for (0 .. $#$entries) {
1148 if ($entries->[$_][1] != DT_DIR) {
1149 # splice out directories
1150 $dirs = [splice @$entries, 0, $_];
1151 last;
1152 }
1153 }
1154
1155 # if we didn't find any non-dir, then all entries are dirs
1156 unless ($dirs) {
1157 ($dirs, $entries) = ($entries, []);
1158 }
1159 } else {
1160 # directory is empty, so there are no sbdirs
1161 $dirs = [];
1162 }
1163
1164 # either splice'd the directories out or the dir was empty.
1165 # convert dents to filenames
1166 $_ = $_->[0] for @$dirs;
1167 $_ = $_->[0] for @$entries;
1168
1169 return $grp->result ($dirs, $entries);
1170 }
1171
1172 # cannot use, so return to our old ways
1173 # by pretending we only scanned for names.
1174 $_ = $_->[0] for @$entries;
1175 }
1021 1176
1022 # stat the dir another time 1177 # stat the dir another time
1023 aioreq_pri $pri; 1178 aioreq_pri $pri;
1024 add $grp aio_stat $wd, sub { 1179 add $grp aio_stat $wd, sub {
1025 my $hash2 = join ":", (stat _)[0,1,3,7,9]; 1180 my $hash2 = join ":", (stat _)[0,1,3,7,9];
… …
1080} 1235}
1081 1236
1082=item aio_rmtree $pathname, $callback->($status) 1237=item aio_rmtree $pathname, $callback->($status)
1083 1238
1084Delete a directory tree starting (and including) C<$path>, return the 1239Delete a directory tree starting (and including) C<$path>, return the
1085status of the final C<rmdir> only. This is a composite request that 1240status of the final C<rmdir> only. This is a composite request that
1086uses C<aio_scandir> to recurse into and rmdir directories, and unlink 1241uses C<aio_scandir> to recurse into and rmdir directories, and unlink
1087everything else. 1242everything else.
1088 1243
1089=cut 1244=cut
1090 1245
… …
1111 add $grp $dirgrp; 1266 add $grp $dirgrp;
1112 }; 1267 };
1113 1268
1114 $grp 1269 $grp
1115} 1270}
1271
1272=item aio_fcntl $fh, $cmd, $arg, $callback->($status)
1273
1274=item aio_ioctl $fh, $request, $buf, $callback->($status)
1275
1276These work just like the C<fcntl> and C<ioctl> built-in functions, except
1277they execute asynchronously and pass the return value to the callback.
1278
1279Both calls can be used for a lot of things, some of which make more sense
1280to run asynchronously in their own thread, while some others make less
1281sense. For example, calls that block waiting for external events, such
1282as locking, will also lock down an I/O thread while it is waiting, which
1283can deadlock the whole I/O system. At the same time, there might be no
1284alternative to using a thread to wait.
1285
1286So in general, you should only use these calls for things that do
1287(filesystem) I/O, not for things that wait for other events (network,
1288other processes), although if you are careful and know what you are doing,
1289you still can.
1290
1291The following constants are available (missing ones are, as usual C<0>):
1292
1293C<F_DUPFD_CLOEXEC>,
1294
1295C<F_OFD_GETLK>, C<F_OFD_SETLK>, C<F_OFD_GETLKW>,
1296
1297C<FIFREEZE>, C<FITHAW>, C<FITRIM>, C<FICLONE>, C<FICLONERANGE>, C<FIDEDUPERANGE>.
1298
1299C<FS_IOC_GETFLAGS>, C<FS_IOC_SETFLAGS>, C<FS_IOC_GETVERSION>, C<FS_IOC_SETVERSION>,
1300C<FS_IOC_FIEMAP>.
1301
1302C<FS_IOC_FSGETXATTR>, C<FS_IOC_FSSETXATTR>, C<FS_IOC_SET_ENCRYPTION_POLICY>,
1303C<FS_IOC_GET_ENCRYPTION_PWSALT>, C<FS_IOC_GET_ENCRYPTION_POLICY>, C<FS_KEY_DESCRIPTOR_SIZE>.
1304
1305C<FS_SECRM_FL>, C<FS_UNRM_FL>, C<FS_COMPR_FL>, C<FS_SYNC_FL>, C<FS_IMMUTABLE_FL>,
1306C<FS_APPEND_FL>, C<FS_NODUMP_FL>, C<FS_NOATIME_FL>, C<FS_DIRTY_FL>,
1307C<FS_COMPRBLK_FL>, C<FS_NOCOMP_FL>, C<FS_ENCRYPT_FL>, C<FS_BTREE_FL>,
1308C<FS_INDEX_FL>, C<FS_JOURNAL_DATA_FL>, C<FS_NOTAIL_FL>, C<FS_DIRSYNC_FL>, C<FS_TOPDIR_FL>,
1309C<FS_FL_USER_MODIFIABLE>.
1310
1311C<FS_XFLAG_REALTIME>, C<FS_XFLAG_PREALLOC>, C<FS_XFLAG_IMMUTABLE>, C<FS_XFLAG_APPEND>,
1312C<FS_XFLAG_SYNC>, C<FS_XFLAG_NOATIME>, C<FS_XFLAG_NODUMP>, C<FS_XFLAG_RTINHERIT>,
1313C<FS_XFLAG_PROJINHERIT>, C<FS_XFLAG_NOSYMLINKS>, C<FS_XFLAG_EXTSIZE>, C<FS_XFLAG_EXTSZINHERIT>,
1314C<FS_XFLAG_NODEFRAG>, C<FS_XFLAG_FILESTREAM>, C<FS_XFLAG_DAX>, C<FS_XFLAG_HASATTR>,
1116 1315
1117=item aio_sync $callback->($status) 1316=item aio_sync $callback->($status)
1118 1317
1119Asynchronously call sync and call the callback when finished. 1318Asynchronously call sync and call the callback when finished.
1120 1319
… …
1189 }; 1388 };
1190 1389
1191 $grp 1390 $grp
1192} 1391}
1193 1392
1194=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 1393=item aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
1195 1394
1196This is a rather advanced IO::AIO call, which only works on mmap(2)ed 1395This is a rather advanced IO::AIO call, which only works on mmap(2)ed
1197scalars (see the C<IO::AIO::mmap> function, although it also works on data 1396scalars (see the C<IO::AIO::mmap> function, although it also works on data
1198scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the 1397scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
1199scalar must only be modified in-place while an aio operation is pending on 1398scalar must only be modified in-place while an aio operation is pending on
… …
1201 1400
1202It calls the C<msync> function of your OS, if available, with the memory 1401It calls the C<msync> function of your OS, if available, with the memory
1203area starting at C<$offset> in the string and ending C<$length> bytes 1402area starting at C<$offset> in the string and ending C<$length> bytes
1204later. If C<$length> is negative, counts from the end, and if C<$length> 1403later. If C<$length> is negative, counts from the end, and if C<$length>
1205is C<undef>, then it goes till the end of the string. The flags can be 1404is C<undef>, then it goes till the end of the string. The flags can be
1206a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and 1405either C<IO::AIO::MS_ASYNC> or C<IO::AIO::MS_SYNC>, plus an optional
1207C<IO::AIO::MS_SYNC>. 1406C<IO::AIO::MS_INVALIDATE>.
1208 1407
1209=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 1408=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1210 1409
1211This is a rather advanced IO::AIO call, which works best on mmap(2)ed 1410This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1212scalars. 1411scalars.
1213 1412
1214It touches (reads or writes) all memory pages in the specified 1413It touches (reads or writes) all memory pages in the specified
1215range inside the scalar. All caveats and parameters are the same 1414range inside the scalar. All caveats and parameters are the same
1216as for C<aio_msync>, above, except for flags, which must be either 1415as for C<aio_msync>, above, except for flags, which must be either
1217C<0> (which reads all pages and ensures they are instantiated) or 1416C<0> (which reads all pages and ensures they are instantiated) or
1218C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and 1417C<IO::AIO::MT_MODIFY>, which modifies the memory pages (by reading and
1219writing an octet from it, which dirties the page). 1418writing an octet from it, which dirties the page).
1220 1419
1221=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) 1420=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
1222 1421
1223This is a rather advanced IO::AIO call, which works best on mmap(2)ed 1422This is a rather advanced IO::AIO call, which works best on mmap(2)ed
… …
1242 IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh; 1441 IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
1243 aio_mlock $data; # mlock in background 1442 aio_mlock $data; # mlock in background
1244 1443
1245=item aio_mlockall $flags, $callback->($status) 1444=item aio_mlockall $flags, $callback->($status)
1246 1445
1247Calls the C<mlockall> function with the given C<$flags> (a combination of 1446Calls the C<mlockall> function with the given C<$flags> (a
1248C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>). 1447combination of C<IO::AIO::MCL_CURRENT>, C<IO::AIO::MCL_FUTURE> and
1448C<IO::AIO::MCL_ONFAULT>).
1249 1449
1250On systems that do not implement C<mlockall>, this function returns C<-1> 1450On systems that do not implement C<mlockall>, this function returns C<-1>
1251and sets errno to C<ENOSYS>. 1451and sets errno to C<ENOSYS>. Similarly, flag combinations not supported
1452by the system result in a return value of C<-1> with errno being set to
1453C<EINVAL>.
1252 1454
1253Note that the corresponding C<munlockall> is synchronous and is 1455Note that the corresponding C<munlockall> is synchronous and is
1254documented under L<MISCELLANEOUS FUNCTIONS>. 1456documented under L<MISCELLANEOUS FUNCTIONS>.
1255 1457
1256Example: asynchronously lock all current and future pages into memory. 1458Example: asynchronously lock all current and future pages into memory.
1257 1459
1258 aio_mlockall IO::AIO::MCL_FUTURE; 1460 aio_mlockall IO::AIO::MCL_FUTURE;
1259 1461
1260=item aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents) 1462=item aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
1261 1463
1262Queries the extents of the given file (by calling the Linux FIEMAP ioctl, 1464Queries the extents of the given file (by calling the Linux C<FIEMAP>
1263see L<http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for details). If the 1465ioctl, see L<http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for details). If
1264C<ioctl> is not available on your OS, then this rquiest will fail with 1466the ioctl is not available on your OS, then this request will fail with
1265C<ENOSYS>. 1467C<ENOSYS>.
1266 1468
1267C<$start> is the starting offset to query extents for, C<$length> is the 1469C<$start> is the starting offset to query extents for, C<$length> is the
1268size of the range to query - if it is C<undef>, then the whole file will 1470size of the range to query - if it is C<undef>, then the whole file will
1269be queried. 1471be queried.
… …
1272C<IO::AIO::FIEMAP_FLAG_XATTR> - C<IO::AIO::FIEMAP_FLAGS_COMPAT> is also 1474C<IO::AIO::FIEMAP_FLAG_XATTR> - C<IO::AIO::FIEMAP_FLAGS_COMPAT> is also
1273exported), and is normally C<0> or C<IO::AIO::FIEMAP_FLAG_SYNC> to query 1475exported), and is normally C<0> or C<IO::AIO::FIEMAP_FLAG_SYNC> to query
1274the data portion. 1476the data portion.
1275 1477
1276C<$count> is the maximum number of extent records to return. If it is 1478C<$count> is the maximum number of extent records to return. If it is
1277C<undef>, then IO::AIO queries all extents of the file. As a very special 1479C<undef>, then IO::AIO queries all extents of the range. As a very special
1278case, if it is C<0>, then the callback receives the number of extents 1480case, if it is C<0>, then the callback receives the number of extents
1279instead of the extents themselves. 1481instead of the extents themselves (which is unreliable, see below).
1280 1482
1281If an error occurs, the callback receives no arguments. The special 1483If an error occurs, the callback receives no arguments. The special
1282C<errno> value C<IO::AIO::EBADR> is available to test for flag errors. 1484C<errno> value C<IO::AIO::EBADR> is available to test for flag errors.
1283 1485
1284Otherwise, the callback receives an array reference with extent 1486Otherwise, the callback receives an array reference with extent
… …
1286following members: 1488following members:
1287 1489
1288 [$logical, $physical, $length, $flags] 1490 [$logical, $physical, $length, $flags]
1289 1491
1290Flags is any combination of the following flag values (typically either C<0> 1492Flags is any combination of the following flag values (typically either C<0>
1291or C<IO::AIO::FIEMAP_EXTENT_LAST>): 1493or C<IO::AIO::FIEMAP_EXTENT_LAST> (1)):
1292 1494
1293C<IO::AIO::FIEMAP_EXTENT_LAST>, C<IO::AIO::FIEMAP_EXTENT_UNKNOWN>, 1495C<IO::AIO::FIEMAP_EXTENT_LAST>, C<IO::AIO::FIEMAP_EXTENT_UNKNOWN>,
1294C<IO::AIO::FIEMAP_EXTENT_DELALLOC>, C<IO::AIO::FIEMAP_EXTENT_ENCODED>, 1496C<IO::AIO::FIEMAP_EXTENT_DELALLOC>, C<IO::AIO::FIEMAP_EXTENT_ENCODED>,
1295C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>, 1497C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
1296C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>, 1498C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
1297C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or 1499C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
1298C<IO::AIO::FIEMAP_EXTENT_SHARED>. 1500C<IO::AIO::FIEMAP_EXTENT_SHARED>.
1299 1501
1502At the time of this writing (Linux 3.2), this request is unreliable unless
1503C<$count> is C<undef>, as the kernel has all sorts of bugs preventing
1504it to return all extents of a range for files with a large number of
1505extents. The code (only) works around all these issues if C<$count> is
1506C<undef>.
1507
1300=item aio_group $callback->(...) 1508=item aio_group $callback->(...)
1301 1509
1302This is a very special aio request: Instead of doing something, it is a 1510This is a very special aio request: Instead of doing something, it is a
1303container for other aio requests, which is useful if you want to bundle 1511container for other aio requests, which is useful if you want to bundle
1304many requests into a single, composite, request with a definite callback 1512many requests into a single, composite, request with a definite callback
… …
1387 aio_stat [$etcdir, "passwd"], sub { 1595 aio_stat [$etcdir, "passwd"], sub {
1388 # yay 1596 # yay
1389 }; 1597 };
1390 }; 1598 };
1391 1599
1392That C<aio_wd> is a request and not a normal function shows that creating 1600The fact that C<aio_wd> is a request and not a normal function shows that
1393an IO::AIO::WD object is itself a potentially blocking operation, which is 1601creating an IO::AIO::WD object is itself a potentially blocking operation,
1394why it is done asynchronously. 1602which is why it is done asynchronously.
1395 1603
1396To stat the directory obtained with C<aio_wd> above, one could write 1604To stat the directory obtained with C<aio_wd> above, one could write
1397either of the following three request calls: 1605either of the following three request calls:
1398 1606
1399 aio_lstat "/etc" , sub { ... # pathname as normal string 1607 aio_lstat "/etc" , sub { ... # pathname as normal string
… …
1416There are some caveats: when directories get renamed (or deleted), the 1624There are some caveats: when directories get renamed (or deleted), the
1417pathname string doesn't change, so will point to the new directory (or 1625pathname string doesn't change, so will point to the new directory (or
1418nowhere at all), while the directory fd, if available on the system, 1626nowhere at all), while the directory fd, if available on the system,
1419will still point to the original directory. Most functions accepting a 1627will still point to the original directory. Most functions accepting a
1420pathname will use the directory fd on newer systems, and the string on 1628pathname will use the directory fd on newer systems, and the string on
1421older systems. Some functions (such as realpath) will always rely on the 1629older systems. Some functions (such as C<aio_realpath>) will always rely on
1422string form of the pathname. 1630the string form of the pathname.
1423 1631
1424So this fucntionality is mainly useful to get some protection against 1632So this functionality is mainly useful to get some protection against
1425C<chdir>, to easily get an absolute path out of a relative path for future 1633C<chdir>, to easily get an absolute path out of a relative path for future
1426reference, and to speed up doing many operations in the same directory 1634reference, and to speed up doing many operations in the same directory
1427(e.g. when stat'ing all files in a directory). 1635(e.g. when stat'ing all files in a directory).
1428 1636
1429The following functions implement this working directory abstraction: 1637The following functions implement this working directory abstraction:
… …
1442passing C<undef> as working directory component of a pathname fails the 1650passing C<undef> as working directory component of a pathname fails the
1443request with C<ENOENT>, there is often no need for error checking in the 1651request with C<ENOENT>, there is often no need for error checking in the
1444C<aio_wd> callback, as future requests using the value will fail in the 1652C<aio_wd> callback, as future requests using the value will fail in the
1445expected way. 1653expected way.
1446 1654
1447If this call isn't available because your OS lacks it or it couldn't be
1448detected, it will be emulated by calling C<fsync> instead.
1449
1450=item IO::AIO::CWD 1655=item IO::AIO::CWD
1451 1656
1452This is a compiletime constant (object) that represents the process 1657This is a compiletime constant (object) that represents the process
1453current working directory. 1658current working directory.
1454 1659
1455Specifying this object as working directory object for a pathname is as 1660Specifying this object as working directory object for a pathname is as if
1456if the pathname would be specified directly, without a directory object, 1661the pathname would be specified directly, without a directory object. For
1457e.g., these calls are functionally identical: 1662example, these calls are functionally identical:
1458 1663
1459 aio_stat "somefile", sub { ... }; 1664 aio_stat "somefile", sub { ... };
1460 aio_stat [IO::AIO::CWD, "somefile"], sub { ... }; 1665 aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
1461 1666
1462=back 1667=back
1463 1668
1669To recover the path associated with an IO::AIO::WD object, you can use
1670C<aio_realpath>:
1671
1672 aio_realpath $wd, sub {
1673 warn "path is $_[0]\n";
1674 };
1675
1676Currently, C<aio_statvfs> always, and C<aio_rename> and C<aio_rmdir>
1677sometimes, fall back to using an absolue path.
1464 1678
1465=head2 IO::AIO::REQ CLASS 1679=head2 IO::AIO::REQ CLASS
1466 1680
1467All non-aggregate C<aio_*> functions return an object of this class when 1681All non-aggregate C<aio_*> functions return an object of this class when
1468called in non-void context. 1682called in non-void context.
… …
1629The default value for the limit is C<0>, but note that setting a feeder 1843The default value for the limit is C<0>, but note that setting a feeder
1630automatically bumps it up to C<2>. 1844automatically bumps it up to C<2>.
1631 1845
1632=back 1846=back
1633 1847
1848
1634=head2 SUPPORT FUNCTIONS 1849=head2 SUPPORT FUNCTIONS
1635 1850
1636=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION 1851=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
1637 1852
1638=over 4 1853=over 4
… …
1646 1861
1647See C<poll_cb> for an example. 1862See C<poll_cb> for an example.
1648 1863
1649=item IO::AIO::poll_cb 1864=item IO::AIO::poll_cb
1650 1865
1651Process some outstanding events on the result pipe. You have to call 1866Process some requests that have reached the result phase (i.e. they have
1867been executed but the results are not yet reported). You have to call
1868this "regularly" to finish outstanding requests.
1869
1652this regularly. Returns C<0> if all events could be processed (or there 1870Returns C<0> if all events could be processed (or there were no
1653were no events to process), or C<-1> if it returned earlier for whatever 1871events to process), or C<-1> if it returned earlier for whatever
1654reason. Returns immediately when no events are outstanding. The amount of 1872reason. Returns immediately when no events are outstanding. The amount
1655events processed depends on the settings of C<IO::AIO::max_poll_req> and 1873of events processed depends on the settings of C<IO::AIO::max_poll_req>,
1656C<IO::AIO::max_poll_time>. 1874C<IO::AIO::max_poll_time> and C<IO::AIO::max_outstanding>.
1657 1875
1658If not all requests were processed for whatever reason, the filehandle 1876If not all requests were processed for whatever reason, the poll file
1659will still be ready when C<poll_cb> returns, so normally you don't have to 1877descriptor will still be ready when C<poll_cb> returns, so normally you
1660do anything special to have it called later. 1878don't have to do anything special to have it called later.
1661 1879
1662Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes 1880Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
1663ready, it can be beneficial to call this function from loops which submit 1881ready, it can be beneficial to call this function from loops which submit
1664a lot of requests, to make sure the results get processed when they become 1882a lot of requests, to make sure the results get processed when they become
1665available and not just when the loop is finished and the event loop takes 1883available and not just when the loop is finished and the event loop takes
… …
1674 poll => 'r', async => 1, 1892 poll => 'r', async => 1,
1675 cb => \&IO::AIO::poll_cb); 1893 cb => \&IO::AIO::poll_cb);
1676 1894
1677=item IO::AIO::poll_wait 1895=item IO::AIO::poll_wait
1678 1896
1679If there are any outstanding requests and none of them in the result 1897Wait until either at least one request is in the result phase or no
1680phase, wait till the result filehandle becomes ready for reading (simply 1898requests are outstanding anymore.
1681does a C<select> on the filehandle. This is useful if you want to 1899
1682synchronously wait for some requests to finish). 1900This is useful if you want to synchronously wait for some requests to
1901become ready, without actually handling them.
1683 1902
1684See C<nreqs> for an example. 1903See C<nreqs> for an example.
1685 1904
1686=item IO::AIO::poll 1905=item IO::AIO::poll
1687 1906
… …
1698 1917
1699Strictly equivalent to: 1918Strictly equivalent to:
1700 1919
1701 IO::AIO::poll_wait, IO::AIO::poll_cb 1920 IO::AIO::poll_wait, IO::AIO::poll_cb
1702 while IO::AIO::nreqs; 1921 while IO::AIO::nreqs;
1922
1923This function can be useful at program aborts, to make sure outstanding
1924I/O has been done (C<IO::AIO> uses an C<END> block which already calls
1925this function on normal exits), or when you are merely using C<IO::AIO>
1926for its more advanced functions, rather than for async I/O, e.g.:
1927
1928 my ($dirs, $nondirs);
1929 IO::AIO::aio_scandir "/tmp", 0, sub { ($dirs, $nondirs) = @_ };
1930 IO::AIO::flush;
1931 # $dirs, $nondirs are now set
1703 1932
1704=item IO::AIO::max_poll_reqs $nreqs 1933=item IO::AIO::max_poll_reqs $nreqs
1705 1934
1706=item IO::AIO::max_poll_time $seconds 1935=item IO::AIO::max_poll_time $seconds
1707 1936
… …
1734 poll => 'r', nice => 1, 1963 poll => 'r', nice => 1,
1735 cb => &IO::AIO::poll_cb); 1964 cb => &IO::AIO::poll_cb);
1736 1965
1737=back 1966=back
1738 1967
1968
1739=head3 CONTROLLING THE NUMBER OF THREADS 1969=head3 CONTROLLING THE NUMBER OF THREADS
1740 1970
1741=over 1971=over
1742 1972
1743=item IO::AIO::min_parallel $nthreads 1973=item IO::AIO::min_parallel $nthreads
… …
1808 2038
1809This is a very bad function to use in interactive programs because it 2039This is a very bad function to use in interactive programs because it
1810blocks, and a bad way to reduce concurrency because it is inexact: Better 2040blocks, and a bad way to reduce concurrency because it is inexact: Better
1811use an C<aio_group> together with a feed callback. 2041use an C<aio_group> together with a feed callback.
1812 2042
1813It's main use is in scripts without an event loop - when you want to stat 2043Its main use is in scripts without an event loop - when you want to stat
1814a lot of files, you can write somehting like this: 2044a lot of files, you can write something like this:
1815 2045
1816 IO::AIO::max_outstanding 32; 2046 IO::AIO::max_outstanding 32;
1817 2047
1818 for my $path (...) { 2048 for my $path (...) {
1819 aio_stat $path , ...; 2049 aio_stat $path , ...;
… …
1830The default value for C<max_outstanding> is very large, so there is no 2060The default value for C<max_outstanding> is very large, so there is no
1831practical limit on the number of outstanding requests. 2061practical limit on the number of outstanding requests.
1832 2062
1833=back 2063=back
1834 2064
2065
1835=head3 STATISTICAL INFORMATION 2066=head3 STATISTICAL INFORMATION
1836 2067
1837=over 2068=over
1838 2069
1839=item IO::AIO::nreqs 2070=item IO::AIO::nreqs
… …
1856Returns the number of requests currently in the pending state (executed, 2087Returns the number of requests currently in the pending state (executed,
1857but not yet processed by poll_cb). 2088but not yet processed by poll_cb).
1858 2089
1859=back 2090=back
1860 2091
2092
2093=head3 SUBSECOND STAT TIME ACCESS
2094
2095Both C<aio_stat>/C<aio_lstat> and perl's C<stat>/C<lstat> functions can
2096generally find access/modification and change times with subsecond time
2097accuracy of the system supports it, but perl's built-in functions only
2098return the integer part.
2099
2100The following functions return the timestamps of the most recent
2101stat with subsecond precision on most systems and work both after
2102C<aio_stat>/C<aio_lstat> and perl's C<stat>/C<lstat> calls. Their return
2103value is only meaningful after a successful C<stat>/C<lstat> call, or
2104during/after a successful C<aio_stat>/C<aio_lstat> callback.
2105
2106This is similar to the L<Time::HiRes> C<stat> functions, but can return
2107full resolution without rounding and work with standard perl C<stat>,
2108alleviating the need to call the special C<Time::HiRes> functions, which
2109do not act like their perl counterparts.
2110
2111On operating systems or file systems where subsecond time resolution is
2112not supported or could not be detected, a fractional part of C<0> is
2113returned, so it is always safe to call these functions.
2114
2115=over 4
2116
2117=item $seconds = IO::AIO::st_atime, IO::AIO::st_mtime, IO::AIO::st_ctime, IO::AIO::st_btime
2118
2119Return the access, modication, change or birth time, respectively,
2120including fractional part. Due to the limited precision of floating point,
2121the accuracy on most platforms is only a bit better than milliseconds
2122for times around now - see the I<nsec> function family, below, for full
2123accuracy.
2124
2125File birth time is only available when the OS and perl support it (on
2126FreeBSD and NetBSD at the time of this writing, although support is
2127adaptive, so if your OS/perl gains support, IO::AIO can take avdantage of
2128it). On systems where it isn't available, C<0> is currently returned, but
2129this might change to C<undef> in a future version.
2130
2131=item ($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtime
2132
2133Returns access, modification, change and birth time all in one go, and
2134maybe more times in the future version.
2135
2136=item $nanoseconds = IO::AIO::st_atimensec, IO::AIO::st_mtimensec, IO::AIO::st_ctimensec, IO::AIO::st_btimensec
2137
2138Return the fractional access, modifcation, change or birth time, in nanoseconds,
2139as an integer in the range C<0> to C<999999999>.
2140
2141Note that no accessors are provided for access, modification and
2142change times - you need to get those from C<stat _> if required (C<int
2143IO::AIO::st_atime> and so on will I<not> generally give you the correct
2144value).
2145
2146=item $seconds = IO::AIO::st_btimesec
2147
2148The (integral) seconds part of the file birth time, if available.
2149
2150=item ($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtimensec
2151
2152Like the functions above, but returns all four times in one go (and maybe
2153more in future versions).
2154
2155=item $counter = IO::AIO::st_gen
2156
2157Returns the generation counter (in practice this is just a random number)
2158of the file. This is only available on platforms which have this member in
2159their C<struct stat> (most BSDs at the time of this writing) and generally
2160only to the root usert. If unsupported, C<0> is returned, but this might
2161change to C<undef> in a future version.
2162
2163=back
2164
2165Example: print the high resolution modification time of F</etc>, using
2166C<stat>, and C<IO::AIO::aio_stat>.
2167
2168 if (stat "/etc") {
2169 printf "stat(/etc) mtime: %f\n", IO::AIO::st_mtime;
2170 }
2171
2172 IO::AIO::aio_stat "/etc", sub {
2173 $_[0]
2174 and return;
2175
2176 printf "aio_stat(/etc) mtime: %d.%09d\n", (stat _)[9], IO::AIO::st_mtimensec;
2177 };
2178
2179 IO::AIO::flush;
2180
2181Output of the awbove on my system, showing reduced and full accuracy:
2182
2183 stat(/etc) mtime: 1534043702.020808
2184 aio_stat(/etc) mtime: 1534043702.020807792
2185
2186
1861=head3 MISCELLANEOUS FUNCTIONS 2187=head3 MISCELLANEOUS FUNCTIONS
1862 2188
1863IO::AIO implements some functions that might be useful, but are not 2189IO::AIO implements some functions that are useful when you want to use
1864asynchronous. 2190some "Advanced I/O" function not available to in Perl, without going the
2191"Asynchronous I/O" route. Many of these have an asynchronous C<aio_*>
2192counterpart.
1865 2193
1866=over 4 2194=over 4
2195
2196=item $numfd = IO::AIO::get_fdlimit
2197
2198This function is I<EXPERIMENTAL> and subject to change.
2199
2200Tries to find the current file descriptor limit and returns it, or
2201C<undef> and sets C<$!> in case of an error. The limit is one larger than
2202the highest valid file descriptor number.
2203
2204=item IO::AIO::min_fdlimit [$numfd]
2205
2206This function is I<EXPERIMENTAL> and subject to change.
2207
2208Try to increase the current file descriptor limit(s) to at least C<$numfd>
2209by changing the soft or hard file descriptor resource limit. If C<$numfd>
2210is missing, it will try to set a very high limit, although this is not
2211recommended when you know the actual minimum that you require.
2212
2213If the limit cannot be raised enough, the function makes a best-effort
2214attempt to increase the limit as much as possible, using various
2215tricks, while still failing. You can query the resulting limit using
2216C<IO::AIO::get_fdlimit>.
2217
2218If an error occurs, returns C<undef> and sets C<$!>, otherwise returns
2219true.
1867 2220
1868=item IO::AIO::sendfile $ofh, $ifh, $offset, $count 2221=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1869 2222
1870Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>, 2223Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
1871but is blocking (this makes most sense if you know the input data is 2224but is blocking (this makes most sense if you know the input data is
… …
1888=item IO::AIO::madvise $scalar, $offset, $len, $advice 2241=item IO::AIO::madvise $scalar, $offset, $len, $advice
1889 2242
1890Simply calls the C<posix_madvise> function (see its 2243Simply calls the C<posix_madvise> function (see its
1891manpage for details). The following advice constants are 2244manpage for details). The following advice constants are
1892available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>, 2245available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
1893C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>. 2246C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>,
2247C<IO::AIO::MADV_DONTNEED>.
2248
2249If C<$offset> is negative, counts from the end. If C<$length> is negative,
2250the remaining length of the C<$scalar> is used. If possible, C<$length>
2251will be reduced to fit into the C<$scalar>.
1894 2252
1895On systems that do not implement C<posix_madvise>, this function returns 2253On systems that do not implement C<posix_madvise>, this function returns
1896ENOSYS, otherwise the return value of C<posix_madvise>. 2254ENOSYS, otherwise the return value of C<posix_madvise>.
1897 2255
1898=item IO::AIO::mprotect $scalar, $offset, $len, $protect 2256=item IO::AIO::mprotect $scalar, $offset, $len, $protect
… …
1900Simply calls the C<mprotect> function on the preferably AIO::mmap'ed 2258Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
1901$scalar (see its manpage for details). The following protect 2259$scalar (see its manpage for details). The following protect
1902constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>, 2260constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
1903C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>. 2261C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
1904 2262
2263If C<$offset> is negative, counts from the end. If C<$length> is negative,
2264the remaining length of the C<$scalar> is used. If possible, C<$length>
2265will be reduced to fit into the C<$scalar>.
2266
1905On systems that do not implement C<mprotect>, this function returns 2267On systems that do not implement C<mprotect>, this function returns
1906ENOSYS, otherwise the return value of C<mprotect>. 2268ENOSYS, otherwise the return value of C<mprotect>.
1907 2269
1908=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset] 2270=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1909 2271
1910Memory-maps a file (or anonymous memory range) and attaches it to the 2272Memory-maps a file (or anonymous memory range) and attaches it to the
1911given C<$scalar>, which will act like a string scalar. 2273given C<$scalar>, which will act like a string scalar. Returns true on
2274success, and false otherwise.
1912 2275
2276The scalar must exist, but its contents do not matter - this means you
2277cannot use a nonexistant array or hash element. When in doubt, C<undef>
2278the scalar first.
2279
1913The only operations allowed on the scalar are C<substr>/C<vec> that don't 2280The only operations allowed on the mmapped scalar are C<substr>/C<vec>,
1914change the string length, and most read-only operations such as copying it 2281which don't change the string length, and most read-only operations such
1915or searching it with regexes and so on. 2282as copying it or searching it with regexes and so on.
1916 2283
1917Anything else is unsafe and will, at best, result in memory leaks. 2284Anything else is unsafe and will, at best, result in memory leaks.
1918 2285
1919The memory map associated with the C<$scalar> is automatically removed 2286The memory map associated with the C<$scalar> is automatically removed
1920when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or 2287when the C<$scalar> is undef'd or destroyed, or when the C<IO::AIO::mmap>
1921C<IO::AIO::munmap> functions are called. 2288or C<IO::AIO::munmap> functions are called on it.
1922 2289
1923This calls the C<mmap>(2) function internally. See your system's manual 2290This calls the C<mmap>(2) function internally. See your system's manual
1924page for details on the C<$length>, C<$prot> and C<$flags> parameters. 2291page for details on the C<$length>, C<$prot> and C<$flags> parameters.
1925 2292
1926The C<$length> must be larger than zero and smaller than the actual 2293The C<$length> must be larger than zero and smaller than the actual
1927filesize. 2294filesize.
1928 2295
1929C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>, 2296C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
1930C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>, 2297C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
1931 2298
1932C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or 2299C<$flags> can be a combination of
1933C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when 2300C<IO::AIO::MAP_SHARED> or
1934not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS> 2301C<IO::AIO::MAP_PRIVATE>,
2302or a number of system-specific flags (when not available, the are C<0>):
1935(which is set to C<MAP_ANON> if your system only provides this 2303C<IO::AIO::MAP_ANONYMOUS> (which is set to C<MAP_ANON> if your system only provides this constant),
1936constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>, 2304C<IO::AIO::MAP_LOCKED>,
1937C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or 2305C<IO::AIO::MAP_NORESERVE>,
2306C<IO::AIO::MAP_POPULATE>,
1938C<IO::AIO::MAP_NONBLOCK> 2307C<IO::AIO::MAP_NONBLOCK>,
2308C<IO::AIO::MAP_FIXED>,
2309C<IO::AIO::MAP_GROWSDOWN>,
2310C<IO::AIO::MAP_32BIT>,
2311C<IO::AIO::MAP_HUGETLB> or
2312C<IO::AIO::MAP_STACK>.
1939 2313
1940If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed. 2314If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
1941 2315
1942C<$offset> is the offset from the start of the file - it generally must be 2316C<$offset> is the offset from the start of the file - it generally must be
1943a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>. 2317a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
… …
1956 my $fast_md5 = md5 $data; 2330 my $fast_md5 = md5 $data;
1957 2331
1958=item IO::AIO::munmap $scalar 2332=item IO::AIO::munmap $scalar
1959 2333
1960Removes a previous mmap and undefines the C<$scalar>. 2334Removes a previous mmap and undefines the C<$scalar>.
2335
2336=item IO::AIO::mremap $scalar, $new_length, $flags = MREMAP_MAYMOVE[, $new_address = 0]
2337
2338Calls the Linux-specific mremap(2) system call. The C<$scalar> must have
2339been mapped by C<IO::AIO::mmap>, and C<$flags> must currently either be
2340C<0> or C<IO::AIO::MREMAP_MAYMOVE>.
2341
2342Returns true if successful, and false otherwise. If the underlying mmapped
2343region has changed address, then the true value has the numerical value
2344C<1>, otherwise it has the numerical value C<0>:
2345
2346 my $success = IO::AIO::mremap $mmapped, 8192, IO::AIO::MREMAP_MAYMOVE
2347 or die "mremap: $!";
2348
2349 if ($success*1) {
2350 warn "scalar has chanegd address in memory\n";
2351 }
2352
2353C<IO::AIO::MREMAP_FIXED> and the C<$new_address> argument are currently
2354implemented, but not supported and might go away in a future version.
2355
2356On systems where this call is not supported or is not emulated, this call
2357returns falls and sets C<$!> to C<ENOSYS>.
2358
2359=item IO::AIO::mlockall $flags
2360
2361Calls the C<eio_mlockall_sync> function, which is like C<aio_mlockall>,
2362but is blocking.
1961 2363
1962=item IO::AIO::munlock $scalar, $offset = 0, $length = undef 2364=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
1963 2365
1964Calls the C<munlock> function, undoing the effects of a previous 2366Calls the C<munlock> function, undoing the effects of a previous
1965C<aio_mlock> call (see its description for details). 2367C<aio_mlock> call (see its description for details).
… …
1975 2377
1976Calls the GNU/Linux C<splice(2)> syscall, if available. If C<$r_off> or 2378Calls the GNU/Linux C<splice(2)> syscall, if available. If C<$r_off> or
1977C<$w_off> are C<undef>, then C<NULL> is passed for these, otherwise they 2379C<$w_off> are C<undef>, then C<NULL> is passed for these, otherwise they
1978should be the file offset. 2380should be the file offset.
1979 2381
2382C<$r_fh> and C<$w_fh> should not refer to the same file, as splice might
2383silently corrupt the data in this case.
2384
1980The following symbol flag values are available: C<IO::AIO::SPLICE_F_MOVE>, 2385The following symbol flag values are available: C<IO::AIO::SPLICE_F_MOVE>,
1981C<IO::AIO::SPLICE_F_NONBLOCK>, C<IO::AIO::SPLICE_F_MORE> and 2386C<IO::AIO::SPLICE_F_NONBLOCK>, C<IO::AIO::SPLICE_F_MORE> and
1982C<IO::AIO::SPLICE_F_GIFT>. 2387C<IO::AIO::SPLICE_F_GIFT>.
1983 2388
1984See the C<splice(2)> manpage for details. 2389See the C<splice(2)> manpage for details.
1985 2390
1986=item IO::AIO::tee $r_fh, $w_fh, $length, $flags 2391=item IO::AIO::tee $r_fh, $w_fh, $length, $flags
1987 2392
1988Calls the GNU/Linux C<tee(2)> syscall, see it's manpage and the 2393Calls the GNU/Linux C<tee(2)> syscall, see its manpage and the
1989description for C<IO::AIO::splice> above for details. 2394description for C<IO::AIO::splice> above for details.
2395
2396=item $actual_size = IO::AIO::pipesize $r_fh[, $new_size]
2397
2398Attempts to query or change the pipe buffer size. Obviously works only
2399on pipes, and currently works only on GNU/Linux systems, and fails with
2400C<-1>/C<ENOSYS> everywhere else. If anybody knows how to influence pipe buffer
2401size on other systems, drop me a note.
2402
2403=item ($rfh, $wfh) = IO::AIO::pipe2 [$flags]
2404
2405This is a direct interface to the Linux L<pipe2(2)> system call. If
2406C<$flags> is missing or C<0>, then this should be the same as a call to
2407perl's built-in C<pipe> function and create a new pipe, and works on
2408systems that lack the pipe2 syscall. On win32, this case invokes C<_pipe
2409(..., 4096, O_BINARY)>.
2410
2411If C<$flags> is non-zero, it tries to invoke the pipe2 system call with
2412the given flags (Linux 2.6.27, glibc 2.9).
2413
2414On success, the read and write file handles are returned.
2415
2416On error, nothing will be returned. If the pipe2 syscall is missing and
2417C<$flags> is non-zero, fails with C<ENOSYS>.
2418
2419Please refer to L<pipe2(2)> for more info on the C<$flags>, but at the
2420time of this writing, C<IO::AIO::O_CLOEXEC>, C<IO::AIO::O_NONBLOCK> and
2421C<IO::AIO::O_DIRECT> (Linux 3.4, for packet-based pipes) were supported.
2422
2423Example: create a pipe race-free w.r.t. threads and fork:
2424
2425 my ($rfh, $wfh) = IO::AIO::pipe2 IO::AIO::O_CLOEXEC
2426 or die "pipe2: $!\n";
2427
2428=item $fh = IO::AIO::eventfd [$initval, [$flags]]
2429
2430This is a direct interface to the Linux L<eventfd(2)> system call. The
2431(unhelpful) defaults for C<$initval> and C<$flags> are C<0> for both.
2432
2433On success, the new eventfd filehandle is returned, otherwise returns
2434C<undef>. If the eventfd syscall is missing, fails with C<ENOSYS>.
2435
2436Please refer to L<eventfd(2)> for more info on this call.
2437
2438The following symbol flag values are available: C<IO::AIO::EFD_CLOEXEC>,
2439C<IO::AIO::EFD_NONBLOCK> and C<IO::AIO::EFD_SEMAPHORE> (Linux 2.6.30).
2440
2441Example: create a new eventfd filehandle:
2442
2443 $fh = IO::AIO::eventfd 0, IO::AIO::O_CLOEXEC
2444 or die "eventfd: $!\n";
2445
2446=item $fh = IO::AIO::timerfd_create $clockid[, $flags]
2447
2448This is a direct interface to the Linux L<timerfd_create(2)> system call. The
2449(unhelpful) default for C<$flags> is C<0>.
2450
2451On success, the new timerfd filehandle is returned, otherwise returns
2452C<undef>. If the eventfd syscall is missing, fails with C<ENOSYS>.
2453
2454Please refer to L<timerfd_create(2)> for more info on this call.
2455
2456The following C<$clockid> values are
2457available: C<IO::AIO::CLOCK_REALTIME>, C<IO::AIO::CLOCK_MONOTONIC>
2458C<IO::AIO::CLOCK_CLOCK_BOOTTIME> (Linux 3.15)
2459C<IO::AIO::CLOCK_CLOCK_REALTIME_ALARM> (Linux 3.11) and
2460C<IO::AIO::CLOCK_CLOCK_BOOTTIME_ALARM> (Linux 3.11).
2461
2462The following C<$flags> values are available (Linux
24632.6.27): C<IO::AIO::TFD_NONBLOCK> and C<IO::AIO::TFD_CLOEXEC>.
2464
2465Example: create a new timerfd and set it to one-second repeated alarms,
2466then wait for two alarms:
2467
2468 my $fh = IO::AIO::timerfd_create IO::AIO::CLOCK_BOOTTIME, IO::AIO::TFD_CLOEXEC
2469 or die "timerfd_create: $!\n";
2470
2471 defined IO::AIO::timerfd_settime $fh, 0, 1, 1
2472 or die "timerfd_settime: $!\n";
2473
2474 for (1..2) {
2475 8 == sysread $fh, my $buf, 8
2476 or die "timerfd read failure\n";
2477
2478 printf "number of expirations (likely 1): %d\n",
2479 unpack "Q", $buf;
2480 }
2481
2482=item ($cur_interval, $cur_value) = IO::AIO::timerfd_settime $fh, $flags, $new_interval, $nbw_value
2483
2484This is a direct interface to the Linux L<timerfd_settime(2)> system
2485call. Please refer to its manpage for more info on this call.
2486
2487The new itimerspec is specified using two (possibly fractional) second
2488values, C<$new_interval> and C<$new_value>).
2489
2490On success, the current interval and value are returned (as per
2491C<timerfd_gettime>). On failure, the empty list is returned.
2492
2493The following C<$flags> values are
2494available: C<IO::AIO::TFD_TIMER_ABSTIME> and
2495C<IO::AIO::TFD_TIMER_CANCEL_ON_SET>.
2496
2497See C<IO::AIO::timerfd_create> for a full example.
2498
2499=item ($cur_interval, $cur_value) = IO::AIO::timerfd_gettime $fh
2500
2501This is a direct interface to the Linux L<timerfd_gettime(2)> system
2502call. Please refer to its manpage for more info on this call.
2503
2504On success, returns the current values of interval and value for the given
2505timerfd (as potentially fractional second values). On failure, the empty
2506list is returned.
1990 2507
1991=back 2508=back
1992 2509
1993=cut 2510=cut
1994 2511
… …
2060the process will result in undefined behaviour. Calling it at any time 2577the process will result in undefined behaviour. Calling it at any time
2061will also result in any undefined (by POSIX) behaviour. 2578will also result in any undefined (by POSIX) behaviour.
2062 2579
2063=back 2580=back
2064 2581
2582=head2 LINUX-SPECIFIC CALLS
2583
2584When a call is documented as "linux-specific" then this means it
2585originated on GNU/Linux. C<IO::AIO> will usually try to autodetect the
2586availability and compatibility of such calls regardless of the platform
2587it is compiled on, so platforms such as FreeBSD which often implement
2588these calls will work. When in doubt, call them and see if they fail wth
2589C<ENOSYS>.
2590
2065=head2 MEMORY USAGE 2591=head2 MEMORY USAGE
2066 2592
2067Per-request usage: 2593Per-request usage:
2068 2594
2069Each aio request uses - depending on your architecture - around 100-200 2595Each aio request uses - depending on your architecture - around 100-200
… …
2081temporary buffers, and each thread requires a stack and other data 2607temporary buffers, and each thread requires a stack and other data
2082structures (usually around 16k-128k, depending on the OS). 2608structures (usually around 16k-128k, depending on the OS).
2083 2609
2084=head1 KNOWN BUGS 2610=head1 KNOWN BUGS
2085 2611
2086Known bugs will be fixed in the next release. 2612Known bugs will be fixed in the next release :)
2613
2614=head1 KNOWN ISSUES
2615
2616Calls that try to "import" foreign memory areas (such as C<IO::AIO::mmap>
2617or C<IO::AIO::aio_slurp>) do not work with generic lvalues, such as
2618non-created hash slots or other scalars I didn't think of. It's best to
2619avoid such and either use scalar variables or making sure that the scalar
2620exists (e.g. by storing C<undef>) and isn't "funny" (e.g. tied).
2621
2622I am not sure anything can be done about this, so this is considered a
2623known issue, rather than a bug.
2087 2624
2088=head1 SEE ALSO 2625=head1 SEE ALSO
2089 2626
2090L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a 2627L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
2091more natural syntax. 2628more natural syntax.

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