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Revision 1.212 by root, Thu Sep 29 22:42:15 2011 UTC vs.
Revision 1.304 by root, Wed Apr 3 03:11:45 2019 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 = '4.0'; 176 our $VERSION = 4.72;
174 177
175 our @AIO_REQ = qw(aio_sendfile 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 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
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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)
218 aio_seek $fh,$offset,$whence, $callback->($offs)
214 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 219 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
215 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 220 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
216 aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) 221 aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
217 aio_readahead $fh,$offset,$length, $callback->($retval) 222 aio_readahead $fh,$offset,$length, $callback->($retval)
218 aio_stat $fh_or_path, $callback->($status) 223 aio_stat $fh_or_path, $callback->($status)
219 aio_lstat $fh, $callback->($status) 224 aio_lstat $fh, $callback->($status)
220 aio_statvfs $fh_or_path, $callback->($statvfs) 225 aio_statvfs $fh_or_path, $callback->($statvfs)
221 aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 226 aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
222 aio_chown $fh_or_path, $uid, $gid, $callback->($status) 227 aio_chown $fh_or_path, $uid, $gid, $callback->($status)
228 aio_chmod $fh_or_path, $mode, $callback->($status)
223 aio_truncate $fh_or_path, $offset, $callback->($status) 229 aio_truncate $fh_or_path, $offset, $callback->($status)
224 aio_chmod $fh_or_path, $mode, $callback->($status) 230 aio_allocate $fh, $mode, $offset, $len, $callback->($status)
231 aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
225 aio_unlink $pathname, $callback->($status) 232 aio_unlink $pathname, $callback->($status)
226 aio_mknod $pathname, $mode, $dev, $callback->($status) 233 aio_mknod $pathname, $mode, $dev, $callback->($status)
227 aio_link $srcpath, $dstpath, $callback->($status) 234 aio_link $srcpath, $dstpath, $callback->($status)
228 aio_symlink $srcpath, $dstpath, $callback->($status) 235 aio_symlink $srcpath, $dstpath, $callback->($status)
229 aio_readlink $pathname, $callback->($link) 236 aio_readlink $pathname, $callback->($link)
230 aio_realpath $pathname, $callback->($link) 237 aio_realpath $pathname, $callback->($path)
231 aio_rename $srcpath, $dstpath, $callback->($status) 238 aio_rename $srcpath, $dstpath, $callback->($status)
239 aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
232 aio_mkdir $pathname, $mode, $callback->($status) 240 aio_mkdir $pathname, $mode, $callback->($status)
233 aio_rmdir $pathname, $callback->($status) 241 aio_rmdir $pathname, $callback->($status)
234 aio_readdir $pathname, $callback->($entries) 242 aio_readdir $pathname, $callback->($entries)
235 aio_readdirx $pathname, $flags, $callback->($entries, $flags) 243 aio_readdirx $pathname, $flags, $callback->($entries, $flags)
236 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST 244 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
237 IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN 245 IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
246 aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
238 aio_load $pathname, $data, $callback->($status) 247 aio_load $pathname, $data, $callback->($status)
239 aio_copy $srcpath, $dstpath, $callback->($status) 248 aio_copy $srcpath, $dstpath, $callback->($status)
240 aio_move $srcpath, $dstpath, $callback->($status) 249 aio_move $srcpath, $dstpath, $callback->($status)
241 aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
242 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)
243 aio_sync $callback->($status) 253 aio_sync $callback->($status)
244 aio_syncfs $fh, $callback->($status) 254 aio_syncfs $fh, $callback->($status)
245 aio_fsync $fh, $callback->($status) 255 aio_fsync $fh, $callback->($status)
246 aio_fdatasync $fh, $callback->($status) 256 aio_fdatasync $fh, $callback->($status)
247 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status) 257 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
248 aio_pathsync $pathname, $callback->($status) 258 aio_pathsync $pathname, $callback->($status)
249 aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 259 aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
250 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 260 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
251 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) 261 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
252 aio_mlockall $flags, $callback->($status) 262 aio_mlockall $flags, $callback->($status)
253 aio_group $callback->(...) 263 aio_group $callback->(...)
254 aio_nop $callback->() 264 aio_nop $callback->()
… …
268 IO::AIO::idle_timeout $seconds 278 IO::AIO::idle_timeout $seconds
269 IO::AIO::max_outstanding $maxreqs 279 IO::AIO::max_outstanding $maxreqs
270 IO::AIO::nreqs 280 IO::AIO::nreqs
271 IO::AIO::nready 281 IO::AIO::nready
272 IO::AIO::npending 282 IO::AIO::npending
283 IO::AIO::reinit
284
285 $nfd = IO::AIO::get_fdlimit [EXPERIMENTAL]
286 IO::AIO::min_fdlimit $nfd [EXPERIMENTAL]
273 287
274 IO::AIO::sendfile $ofh, $ifh, $offset, $count 288 IO::AIO::sendfile $ofh, $ifh, $offset, $count
275 IO::AIO::fadvise $fh, $offset, $len, $advice 289 IO::AIO::fadvise $fh, $offset, $len, $advice
290
291 IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
292 IO::AIO::munmap $scalar
293 IO::AIO::mremap $scalar, $new_length, $flags[, $new_address]
276 IO::AIO::madvise $scalar, $offset, $length, $advice 294 IO::AIO::madvise $scalar, $offset, $length, $advice
277 IO::AIO::mprotect $scalar, $offset, $length, $protect 295 IO::AIO::mprotect $scalar, $offset, $length, $protect
278 IO::AIO::munlock $scalar, $offset = 0, $length = undef 296 IO::AIO::munlock $scalar, $offset = 0, $length = undef
279 IO::AIO::munlockall 297 IO::AIO::munlockall
280 298
281=head2 AIO REQUEST FUNCTIONS 299 # stat extensions
300 $counter = IO::AIO::st_gen
301 $seconds = IO::AIO::st_atime, IO::AIO::st_mtime, IO::AIO::st_ctime, IO::AIO::st_btime
302 ($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtime
303 $nanoseconds = IO::AIO::st_atimensec, IO::AIO::st_mtimensec, IO::AIO::st_ctimensec, IO::AIO::st_btimensec
304 $seconds = IO::AIO::st_btimesec
305 ($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtimensec
306
307 # very much unportable syscalls
308 IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
309 IO::AIO::tee $r_fh, $w_fh, $length, $flags
310 $actual_size = IO::AIO::pipesize $r_fh[, $new_size]
311 ($rfh, $wfh) = IO::AIO::pipe2 [$flags]
312 $fh = IO::AIO::memfd_create $pathname[, $flags]
313 $fh = IO::AIO::eventfd [$initval, [$flags]]
314 $fh = IO::AIO::timerfd_create $clockid[, $flags]
315 ($cur_interval, $cur_value) = IO::AIO::timerfd_settime $fh, $flags, $new_interval, $nbw_value
316 ($cur_interval, $cur_value) = IO::AIO::timerfd_gettime $fh
317
318=head2 API NOTES
282 319
283All the C<aio_*> calls are more or less thin wrappers around the syscall 320All the C<aio_*> calls are more or less thin wrappers around the syscall
284with the same name (sans C<aio_>). The arguments are similar or identical, 321with the same name (sans C<aio_>). The arguments are similar or identical,
285and they all accept an additional (and optional) C<$callback> argument 322and they all accept an additional (and optional) C<$callback> argument
286which must be a code reference. This code reference will be called after 323which must be a code reference. This code reference will be called after
… …
317correct contents. 354correct contents.
318 355
319This works, btw. independent of the internal UTF-8 bit, which IO::AIO 356This works, btw. independent of the internal UTF-8 bit, which IO::AIO
320handles correctly whether it is set or not. 357handles correctly whether it is set or not.
321 358
359=head2 AIO REQUEST FUNCTIONS
360
322=over 4 361=over 4
323 362
324=item $prev_pri = aioreq_pri [$pri] 363=item $prev_pri = aioreq_pri [$pri]
325 364
326Returns the priority value that would be used for the next request and, if 365Returns the priority value that would be used for the next request and, if
… …
355 394
356 395
357=item aio_open $pathname, $flags, $mode, $callback->($fh) 396=item aio_open $pathname, $flags, $mode, $callback->($fh)
358 397
359Asynchronously open or create a file and call the callback with a newly 398Asynchronously open or create a file and call the callback with a newly
360created filehandle for the file. 399created filehandle for the file (or C<undef> in case of an error).
361 400
362The pathname passed to C<aio_open> must be absolute. See API NOTES, above, 401The pathname passed to C<aio_open> must be absolute. See API NOTES, above,
363for an explanation. 402for an explanation.
364 403
365The C<$flags> argument is a bitmask. See the C<Fcntl> module for a 404The C<$flags> argument is a bitmask. See the C<Fcntl> module for a
… …
388following POSIX and non-POSIX constants are available (missing ones on 427following POSIX and non-POSIX constants are available (missing ones on
389your system are, as usual, C<0>): 428your system are, as usual, C<0>):
390 429
391C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>, 430C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,
392C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>, 431C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,
393C<O_RSYNC>, C<O_SYNC> and C<O_TTY_INIT>. 432C<O_RSYNC>, C<O_SYNC>, C<O_PATH>, C<O_TMPFILE>, C<O_TTY_INIT> and C<O_ACCMODE>.
394 433
395 434
396=item aio_close $fh, $callback->($status) 435=item aio_close $fh, $callback->($status)
397 436
398Asynchronously close a file and call the callback with the result 437Asynchronously close a file and call the callback with the result
… …
408Or in other words: the file descriptor will be closed, but it will not be 447Or in other words: the file descriptor will be closed, but it will not be
409free for reuse until the perl filehandle is closed. 448free for reuse until the perl filehandle is closed.
410 449
411=cut 450=cut
412 451
452=item aio_seek $fh, $offset, $whence, $callback->($offs)
453
454Seeks the filehandle to the new C<$offset>, similarly to perl's
455C<sysseek>. The C<$whence> can use the traditional values (C<0> for
456C<IO::AIO::SEEK_SET>, C<1> for C<IO::AIO::SEEK_CUR> or C<2> for
457C<IO::AIO::SEEK_END>).
458
459The resulting absolute offset will be passed to the callback, or C<-1> in
460case of an error.
461
462In theory, the C<$whence> constants could be different than the
463corresponding values from L<Fcntl>, but perl guarantees they are the same,
464so don't panic.
465
466As a GNU/Linux (and maybe Solaris) extension, also the constants
467C<IO::AIO::SEEK_DATA> and C<IO::AIO::SEEK_HOLE> are available, if they
468could be found. No guarantees about suitability for use in C<aio_seek> or
469Perl's C<sysseek> can be made though, although I would naively assume they
470"just work".
471
413=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 472=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
414 473
415=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 474=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
416 475
417Reads or writes C<$length> bytes from or to the specified C<$fh> and 476Reads or writes C<$length> bytes from or to the specified C<$fh> and
418C<$offset> into the scalar given by C<$data> and offset C<$dataoffset> 477C<$offset> into the scalar given by C<$data> and offset C<$dataoffset> and
419and calls the callback without the actual number of bytes read (or -1 on 478calls the callback with the actual number of bytes transferred (or -1 on
420error, just like the syscall). 479error, just like the syscall).
421 480
422C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to 481C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
423offset plus the actual number of bytes read. 482offset plus the actual number of bytes read.
424 483
… …
482As native sendfile syscalls (as practically any non-POSIX interface hacked 541As native sendfile syscalls (as practically any non-POSIX interface hacked
483together in a hurry to improve benchmark numbers) tend to be rather buggy 542together in a hurry to improve benchmark numbers) tend to be rather buggy
484on many systems, this implementation tries to work around some known bugs 543on many systems, this implementation tries to work around some known bugs
485in Linux and FreeBSD kernels (probably others, too), but that might fail, 544in Linux and FreeBSD kernels (probably others, too), but that might fail,
486so you really really should check the return value of C<aio_sendfile> - 545so you really really should check the return value of C<aio_sendfile> -
487fewre bytes than expected might have been transferred. 546fewer bytes than expected might have been transferred.
488 547
489 548
490=item aio_readahead $fh,$offset,$length, $callback->($retval) 549=item aio_readahead $fh,$offset,$length, $callback->($retval)
491 550
492C<aio_readahead> populates the page cache with data from a file so that 551C<aio_readahead> populates the page cache with data from a file so that
… …
496whole pages, so that offset is effectively rounded down to a page boundary 555whole pages, so that offset is effectively rounded down to a page boundary
497and bytes are read up to the next page boundary greater than or equal to 556and bytes are read up to the next page boundary greater than or equal to
498(off-set+length). C<aio_readahead> does not read beyond the end of the 557(off-set+length). C<aio_readahead> does not read beyond the end of the
499file. The current file offset of the file is left unchanged. 558file. The current file offset of the file is left unchanged.
500 559
501If that syscall doesn't exist (likely if your OS isn't Linux) it will be 560If that syscall doesn't exist (likely if your kernel isn't Linux) it will
502emulated by simply reading the data, which would have a similar effect. 561be emulated by simply reading the data, which would have a similar effect.
503 562
504 563
505=item aio_stat $fh_or_path, $callback->($status) 564=item aio_stat $fh_or_path, $callback->($status)
506 565
507=item aio_lstat $fh, $callback->($status) 566=item aio_lstat $fh, $callback->($status)
508 567
509Works like perl's C<stat> or C<lstat> in void context. The callback will 568Works almost exactly like perl's C<stat> or C<lstat> in void context. The
510be called after the stat and the results will be available using C<stat _> 569callback will be called after the stat and the results will be available
511or C<-s _> etc... 570using C<stat _> or C<-s _> and other tests (with the exception of C<-B>
571and C<-T>).
512 572
513The pathname passed to C<aio_stat> must be absolute. See API NOTES, above, 573The pathname passed to C<aio_stat> must be absolute. See API NOTES, above,
514for an explanation. 574for an explanation.
515 575
516Currently, the stats are always 64-bit-stats, i.e. instead of returning an 576Currently, the stats are always 64-bit-stats, i.e. instead of returning an
… …
523behaviour). 583behaviour).
524 584
525C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>, 585C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>,
526C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>, 586C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>,
527C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>. 587C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>.
588
589To access higher resolution stat timestamps, see L<SUBSECOND STAT TIME
590ACCESS>.
528 591
529Example: Print the length of F</etc/passwd>: 592Example: Print the length of F</etc/passwd>:
530 593
531 aio_stat "/etc/passwd", sub { 594 aio_stat "/etc/passwd", sub {
532 $_[0] and die "stat failed: $!"; 595 $_[0] and die "stat failed: $!";
… …
576 namemax => 255, 639 namemax => 255,
577 frsize => 1024, 640 frsize => 1024,
578 fsid => 1810 641 fsid => 1810
579 } 642 }
580 643
581
582=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 644=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
583 645
584Works like perl's C<utime> function (including the special case of $atime 646Works like perl's C<utime> function (including the special case of $atime
585and $mtime being undef). Fractional times are supported if the underlying 647and $mtime being undef). Fractional times are supported if the underlying
586syscalls support them. 648syscalls support them.
587 649
588When called with a pathname, uses utimes(2) if available, otherwise 650When called with a pathname, uses utimensat(2) or utimes(2) if available,
589utime(2). If called on a file descriptor, uses futimes(2) if available, 651otherwise utime(2). If called on a file descriptor, uses futimens(2)
590otherwise returns ENOSYS, so this is not portable. 652or futimes(2) if available, otherwise returns ENOSYS, so this is not
653portable.
591 654
592Examples: 655Examples:
593 656
594 # set atime and mtime to current time (basically touch(1)): 657 # set atime and mtime to current time (basically touch(1)):
595 aio_utime "path", undef, undef; 658 aio_utime "path", undef, undef;
… …
613=item aio_truncate $fh_or_path, $offset, $callback->($status) 676=item aio_truncate $fh_or_path, $offset, $callback->($status)
614 677
615Works like truncate(2) or ftruncate(2). 678Works like truncate(2) or ftruncate(2).
616 679
617 680
681=item aio_allocate $fh, $mode, $offset, $len, $callback->($status)
682
683Allocates or frees disk space according to the C<$mode> argument. See the
684linux C<fallocate> documentation for details.
685
686C<$mode> is usually C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE> to allocate
687space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE | IO::AIO::FALLOC_FL_KEEP_SIZE>,
688to deallocate a file range.
689
690IO::AIO also supports C<FALLOC_FL_COLLAPSE_RANGE>, to remove a range
691(without leaving a hole), C<FALLOC_FL_ZERO_RANGE>, to zero a range,
692C<FALLOC_FL_INSERT_RANGE> to insert a range and C<FALLOC_FL_UNSHARE_RANGE>
693to unshare shared blocks (see your L<fallocate(2)> manpage).
694
695The file system block size used by C<fallocate> is presumably the
696C<f_bsize> returned by C<statvfs>, but different filesystems and filetypes
697can dictate other limitations.
698
699If C<fallocate> isn't available or cannot be emulated (currently no
700emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>.
701
702
618=item aio_chmod $fh_or_path, $mode, $callback->($status) 703=item aio_chmod $fh_or_path, $mode, $callback->($status)
619 704
620Works like perl's C<chmod> function. 705Works like perl's C<chmod> function.
621 706
622 707
… …
659 744
660 745
661=item aio_realpath $pathname, $callback->($path) 746=item aio_realpath $pathname, $callback->($path)
662 747
663Asynchronously make the path absolute and resolve any symlinks in 748Asynchronously make the path absolute and resolve any symlinks in
664C<$path>. The resulting path only consists of directories (Same as 749C<$path>. The resulting path only consists of directories (same as
665L<Cwd::realpath>). 750L<Cwd::realpath>).
666 751
667This request can be used to get the absolute path of the current working 752This request can be used to get the absolute path of the current working
668directory by passing it a path of F<.> (a single dot). 753directory by passing it a path of F<.> (a single dot).
669 754
670 755
671=item aio_rename $srcpath, $dstpath, $callback->($status) 756=item aio_rename $srcpath, $dstpath, $callback->($status)
672 757
673Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as 758Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
674rename(2) and call the callback with the result code. 759rename(2) and call the callback with the result code.
760
761On systems that support the AIO::WD working directory abstraction
762natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead
763of failing, C<rename> is called on the absolute path of C<$wd>.
764
765
766=item aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
767
768Basically a version of C<aio_rename> with an additional C<$flags>
769argument. Calling this with C<$flags=0> is the same as calling
770C<aio_rename>.
771
772Non-zero flags are currently only supported on GNU/Linux systems that
773support renameat2. Other systems fail with C<ENOSYS> in this case.
774
775The following constants are available (missing ones are, as usual C<0>),
776see renameat2(2) for details:
777
778C<IO::AIO::RENAME_NOREPLACE>, C<IO::AIO::RENAME_EXCHANGE>
779and C<IO::AIO::RENAME_WHITEOUT>.
675 780
676 781
677=item aio_mkdir $pathname, $mode, $callback->($status) 782=item aio_mkdir $pathname, $mode, $callback->($status)
678 783
679Asynchronously mkdir (create) a directory and call the callback with 784Asynchronously mkdir (create) a directory and call the callback with
… …
684=item aio_rmdir $pathname, $callback->($status) 789=item aio_rmdir $pathname, $callback->($status)
685 790
686Asynchronously rmdir (delete) a directory and call the callback with the 791Asynchronously rmdir (delete) a directory and call the callback with the
687result code. 792result code.
688 793
794On systems that support the AIO::WD working directory abstraction
795natively, the case C<[$wd, "."]> is specialcased - instead of failing,
796C<rmdir> is called on the absolute path of C<$wd>.
797
689 798
690=item aio_readdir $pathname, $callback->($entries) 799=item aio_readdir $pathname, $callback->($entries)
691 800
692Unlike the POSIX call of the same name, C<aio_readdir> reads an entire 801Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
693directory (i.e. opendir + readdir + closedir). The entries will not be 802directory (i.e. opendir + readdir + closedir). The entries will not be
… …
708 817
709=over 4 818=over 4
710 819
711=item IO::AIO::READDIR_DENTS 820=item IO::AIO::READDIR_DENTS
712 821
713When this flag is off, then the callback gets an arrayref consisting of 822Normally the callback gets an arrayref consisting of names only (as
714names only (as with C<aio_readdir>), otherwise it gets an arrayref with 823with C<aio_readdir>). If this flag is set, then the callback gets an
715C<[$name, $type, $inode]> arrayrefs, each describing a single directory 824arrayref with C<[$name, $type, $inode]> arrayrefs, each describing a
716entry in more detail. 825single directory entry in more detail:
717 826
718C<$name> is the name of the entry. 827C<$name> is the name of the entry.
719 828
720C<$type> is one of the C<IO::AIO::DT_xxx> constants: 829C<$type> is one of the C<IO::AIO::DT_xxx> constants:
721 830
722C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>, 831C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
723C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>, 832C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
724C<IO::AIO::DT_WHT>. 833C<IO::AIO::DT_WHT>.
725 834
726C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to 835C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need
727know, you have to run stat yourself. Also, for speed reasons, the C<$type> 836to know, you have to run stat yourself. Also, for speed/memory reasons,
728scalars are read-only: you can not modify them. 837the C<$type> scalars are read-only: you must not modify them.
729 838
730C<$inode> is the inode number (which might not be exact on systems with 64 839C<$inode> is the inode number (which might not be exact on systems with 64
731bit inode numbers and 32 bit perls). This field has unspecified content on 840bit inode numbers and 32 bit perls). This field has unspecified content on
732systems that do not deliver the inode information. 841systems that do not deliver the inode information.
733 842
… …
744short names are tried first. 853short names are tried first.
745 854
746=item IO::AIO::READDIR_STAT_ORDER 855=item IO::AIO::READDIR_STAT_ORDER
747 856
748When this flag is set, then the names will be returned in an order 857When this flag is set, then the names will be returned in an order
749suitable for stat()'ing each one. That is, when you plan to stat() 858suitable for stat()'ing each one. That is, when you plan to stat() most or
750all files in the given directory, then the returned order will likely 859all files in the given directory, then the returned order will likely be
751be fastest. 860faster.
752 861
753If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then 862If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified,
754the likely dirs come first, resulting in a less optimal stat order. 863then the likely dirs come first, resulting in a less optimal stat order
864for stat'ing all entries, but likely a more optimal order for finding
865subdirectories.
755 866
756=item IO::AIO::READDIR_FOUND_UNKNOWN 867=item IO::AIO::READDIR_FOUND_UNKNOWN
757 868
758This flag should not be set when calling C<aio_readdirx>. Instead, it 869This flag should not be set when calling C<aio_readdirx>. Instead, it
759is being set by C<aio_readdirx>, when any of the C<$type>'s found were 870is being set by C<aio_readdirx>, when any of the C<$type>'s found were
… …
761C<$type>'s are known, which can be used to speed up some algorithms. 872C<$type>'s are known, which can be used to speed up some algorithms.
762 873
763=back 874=back
764 875
765 876
877=item aio_slurp $pathname, $offset, $length, $data, $callback->($status)
878
879Opens, reads and closes the given file. The data is put into C<$data>,
880which is resized as required.
881
882If C<$offset> is negative, then it is counted from the end of the file.
883
884If C<$length> is zero, then the remaining length of the file is
885used. Also, in this case, the same limitations to modifying C<$data> apply
886as when IO::AIO::mmap is used, i.e. it must only be modified in-place
887with C<substr>. If the size of the file is known, specifying a non-zero
888C<$length> results in a performance advantage.
889
890This request is similar to the older C<aio_load> request, but since it is
891a single request, it might be more efficient to use.
892
893Example: load F</etc/passwd> into C<$passwd>.
894
895 my $passwd;
896 aio_slurp "/etc/passwd", 0, 0, $passwd, sub {
897 $_[0] >= 0
898 or die "/etc/passwd: $!\n";
899
900 printf "/etc/passwd is %d bytes long, and contains:\n", length $passwd;
901 print $passwd;
902 };
903 IO::AIO::flush;
904
905
766=item aio_load $pathname, $data, $callback->($status) 906=item aio_load $pathname, $data, $callback->($status)
767 907
768This is a composite request that tries to fully load the given file into 908This is a composite request that tries to fully load the given file into
769memory. Status is the same as with aio_read. 909memory. Status is the same as with aio_read.
910
911Using C<aio_slurp> might be more efficient, as it is a single request.
770 912
771=cut 913=cut
772 914
773sub aio_load($$;$) { 915sub aio_load($$;$) {
774 my ($path, undef, $cb) = @_; 916 my ($path, undef, $cb) = @_;
… …
794=item aio_copy $srcpath, $dstpath, $callback->($status) 936=item aio_copy $srcpath, $dstpath, $callback->($status)
795 937
796Try to copy the I<file> (directories not supported as either source or 938Try to copy the I<file> (directories not supported as either source or
797destination) from C<$srcpath> to C<$dstpath> and call the callback with 939destination) from C<$srcpath> to C<$dstpath> and call the callback with
798a status of C<0> (ok) or C<-1> (error, see C<$!>). 940a status of C<0> (ok) or C<-1> (error, see C<$!>).
941
942Existing destination files will be truncated.
799 943
800This is a composite request that creates the destination file with 944This is a composite request that creates the destination file with
801mode 0200 and copies the contents of the source file into it using 945mode 0200 and copies the contents of the source file into it using
802C<aio_sendfile>, followed by restoring atime, mtime, access mode and 946C<aio_sendfile>, followed by restoring atime, mtime, access mode and
803uid/gid, in that order. 947uid/gid, in that order.
… …
913Scans a directory (similar to C<aio_readdir>) but additionally tries to 1057Scans a directory (similar to C<aio_readdir>) but additionally tries to
914efficiently separate the entries of directory C<$path> into two sets of 1058efficiently separate the entries of directory C<$path> into two sets of
915names, directories you can recurse into (directories), and ones you cannot 1059names, directories you can recurse into (directories), and ones you cannot
916recurse into (everything else, including symlinks to directories). 1060recurse into (everything else, including symlinks to directories).
917 1061
918C<aio_scandir> is a composite request that creates of many sub requests_ 1062C<aio_scandir> is a composite request that generates many sub requests.
919C<$maxreq> specifies the maximum number of outstanding aio requests that 1063C<$maxreq> specifies the maximum number of outstanding aio requests that
920this function generates. If it is C<< <= 0 >>, then a suitable default 1064this function generates. If it is C<< <= 0 >>, then a suitable default
921will be chosen (currently 4). 1065will be chosen (currently 4).
922 1066
923On error, the callback is called without arguments, otherwise it receives 1067On error, the callback is called without arguments, otherwise it receives
… …
987 aioreq_pri $pri; 1131 aioreq_pri $pri;
988 add $grp aio_stat $wd, sub { 1132 add $grp aio_stat $wd, sub {
989 return $grp->result () if $_[0]; 1133 return $grp->result () if $_[0];
990 my $now = time; 1134 my $now = time;
991 my $hash1 = join ":", (stat _)[0,1,3,7,9]; 1135 my $hash1 = join ":", (stat _)[0,1,3,7,9];
1136 my $rdxflags = READDIR_DIRS_FIRST;
1137
1138 if ((stat _)[3] < 2) {
1139 # at least one non-POSIX filesystem exists
1140 # that returns useful DT_type values: btrfs,
1141 # so optimise for this here by requesting dents
1142 $rdxflags |= READDIR_DENTS;
1143 }
992 1144
993 # read the directory entries 1145 # read the directory entries
994 aioreq_pri $pri; 1146 aioreq_pri $pri;
995 add $grp aio_readdirx $wd, READDIR_DIRS_FIRST, sub { 1147 add $grp aio_readdirx $wd, $rdxflags, sub {
996 my $entries = shift 1148 my ($entries, $flags) = @_
997 or return $grp->result (); 1149 or return $grp->result ();
1150
1151 if ($rdxflags & READDIR_DENTS) {
1152 # if we requested type values, see if we can use them directly.
1153
1154 # if there were any DT_UNKNOWN entries then we assume we
1155 # don't know. alternatively, we could assume that if we get
1156 # one DT_DIR, then all directories are indeed marked with
1157 # DT_DIR, but this seems not required for btrfs, and this
1158 # is basically the "btrfs can't get it's act together" code
1159 # branch.
1160 unless ($flags & READDIR_FOUND_UNKNOWN) {
1161 # now we have valid DT_ information for all entries,
1162 # so use it as an optimisation without further stat's.
1163 # they must also all be at the beginning of @$entries
1164 # by now.
1165
1166 my $dirs;
1167
1168 if (@$entries) {
1169 for (0 .. $#$entries) {
1170 if ($entries->[$_][1] != DT_DIR) {
1171 # splice out directories
1172 $dirs = [splice @$entries, 0, $_];
1173 last;
1174 }
1175 }
1176
1177 # if we didn't find any non-dir, then all entries are dirs
1178 unless ($dirs) {
1179 ($dirs, $entries) = ($entries, []);
1180 }
1181 } else {
1182 # directory is empty, so there are no sbdirs
1183 $dirs = [];
1184 }
1185
1186 # either splice'd the directories out or the dir was empty.
1187 # convert dents to filenames
1188 $_ = $_->[0] for @$dirs;
1189 $_ = $_->[0] for @$entries;
1190
1191 return $grp->result ($dirs, $entries);
1192 }
1193
1194 # cannot use, so return to our old ways
1195 # by pretending we only scanned for names.
1196 $_ = $_->[0] for @$entries;
1197 }
998 1198
999 # stat the dir another time 1199 # stat the dir another time
1000 aioreq_pri $pri; 1200 aioreq_pri $pri;
1001 add $grp aio_stat $wd, sub { 1201 add $grp aio_stat $wd, sub {
1002 my $hash2 = join ":", (stat _)[0,1,3,7,9]; 1202 my $hash2 = join ":", (stat _)[0,1,3,7,9];
… …
1057} 1257}
1058 1258
1059=item aio_rmtree $pathname, $callback->($status) 1259=item aio_rmtree $pathname, $callback->($status)
1060 1260
1061Delete a directory tree starting (and including) C<$path>, return the 1261Delete a directory tree starting (and including) C<$path>, return the
1062status of the final C<rmdir> only. This is a composite request that 1262status of the final C<rmdir> only. This is a composite request that
1063uses C<aio_scandir> to recurse into and rmdir directories, and unlink 1263uses C<aio_scandir> to recurse into and rmdir directories, and unlink
1064everything else. 1264everything else.
1065 1265
1066=cut 1266=cut
1067 1267
… …
1088 add $grp $dirgrp; 1288 add $grp $dirgrp;
1089 }; 1289 };
1090 1290
1091 $grp 1291 $grp
1092} 1292}
1293
1294=item aio_fcntl $fh, $cmd, $arg, $callback->($status)
1295
1296=item aio_ioctl $fh, $request, $buf, $callback->($status)
1297
1298These work just like the C<fcntl> and C<ioctl> built-in functions, except
1299they execute asynchronously and pass the return value to the callback.
1300
1301Both calls can be used for a lot of things, some of which make more sense
1302to run asynchronously in their own thread, while some others make less
1303sense. For example, calls that block waiting for external events, such
1304as locking, will also lock down an I/O thread while it is waiting, which
1305can deadlock the whole I/O system. At the same time, there might be no
1306alternative to using a thread to wait.
1307
1308So in general, you should only use these calls for things that do
1309(filesystem) I/O, not for things that wait for other events (network,
1310other processes), although if you are careful and know what you are doing,
1311you still can.
1312
1313The following constants are available and can be used for normal C<ioctl>
1314and C<fcntl> as well (missing ones are, as usual C<0>):
1315
1316C<F_DUPFD_CLOEXEC>,
1317
1318C<F_OFD_GETLK>, C<F_OFD_SETLK>, C<F_OFD_GETLKW>,
1319
1320C<FIFREEZE>, C<FITHAW>, C<FITRIM>, C<FICLONE>, C<FICLONERANGE>, C<FIDEDUPERANGE>.
1321
1322C<F_ADD_SEALS>, C<F_GET_SEALS>, C<F_SEAL_SEAL>, C<F_SEAL_SHRINK>, C<F_SEAL_GROW> and
1323C<F_SEAL_WRITE>.
1324
1325C<FS_IOC_GETFLAGS>, C<FS_IOC_SETFLAGS>, C<FS_IOC_GETVERSION>, C<FS_IOC_SETVERSION>,
1326C<FS_IOC_FIEMAP>.
1327
1328C<FS_IOC_FSGETXATTR>, C<FS_IOC_FSSETXATTR>, C<FS_IOC_SET_ENCRYPTION_POLICY>,
1329C<FS_IOC_GET_ENCRYPTION_PWSALT>, C<FS_IOC_GET_ENCRYPTION_POLICY>, C<FS_KEY_DESCRIPTOR_SIZE>.
1330
1331C<FS_SECRM_FL>, C<FS_UNRM_FL>, C<FS_COMPR_FL>, C<FS_SYNC_FL>, C<FS_IMMUTABLE_FL>,
1332C<FS_APPEND_FL>, C<FS_NODUMP_FL>, C<FS_NOATIME_FL>, C<FS_DIRTY_FL>,
1333C<FS_COMPRBLK_FL>, C<FS_NOCOMP_FL>, C<FS_ENCRYPT_FL>, C<FS_BTREE_FL>,
1334C<FS_INDEX_FL>, C<FS_JOURNAL_DATA_FL>, C<FS_NOTAIL_FL>, C<FS_DIRSYNC_FL>, C<FS_TOPDIR_FL>,
1335C<FS_FL_USER_MODIFIABLE>.
1336
1337C<FS_XFLAG_REALTIME>, C<FS_XFLAG_PREALLOC>, C<FS_XFLAG_IMMUTABLE>, C<FS_XFLAG_APPEND>,
1338C<FS_XFLAG_SYNC>, C<FS_XFLAG_NOATIME>, C<FS_XFLAG_NODUMP>, C<FS_XFLAG_RTINHERIT>,
1339C<FS_XFLAG_PROJINHERIT>, C<FS_XFLAG_NOSYMLINKS>, C<FS_XFLAG_EXTSIZE>, C<FS_XFLAG_EXTSZINHERIT>,
1340C<FS_XFLAG_NODEFRAG>, C<FS_XFLAG_FILESTREAM>, C<FS_XFLAG_DAX>, C<FS_XFLAG_HASATTR>,
1093 1341
1094=item aio_sync $callback->($status) 1342=item aio_sync $callback->($status)
1095 1343
1096Asynchronously call sync and call the callback when finished. 1344Asynchronously call sync and call the callback when finished.
1097 1345
… …
1166 }; 1414 };
1167 1415
1168 $grp 1416 $grp
1169} 1417}
1170 1418
1171=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 1419=item aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
1172 1420
1173This is a rather advanced IO::AIO call, which only works on mmap(2)ed 1421This is a rather advanced IO::AIO call, which only works on mmap(2)ed
1174scalars (see the C<IO::AIO::mmap> function, although it also works on data 1422scalars (see the C<IO::AIO::mmap> function, although it also works on data
1175scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the 1423scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
1176scalar must only be modified in-place while an aio operation is pending on 1424scalar must only be modified in-place while an aio operation is pending on
… …
1178 1426
1179It calls the C<msync> function of your OS, if available, with the memory 1427It calls the C<msync> function of your OS, if available, with the memory
1180area starting at C<$offset> in the string and ending C<$length> bytes 1428area starting at C<$offset> in the string and ending C<$length> bytes
1181later. If C<$length> is negative, counts from the end, and if C<$length> 1429later. If C<$length> is negative, counts from the end, and if C<$length>
1182is C<undef>, then it goes till the end of the string. The flags can be 1430is C<undef>, then it goes till the end of the string. The flags can be
1183a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and 1431either C<IO::AIO::MS_ASYNC> or C<IO::AIO::MS_SYNC>, plus an optional
1184C<IO::AIO::MS_SYNC>. 1432C<IO::AIO::MS_INVALIDATE>.
1185 1433
1186=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 1434=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1187 1435
1188This is a rather advanced IO::AIO call, which works best on mmap(2)ed 1436This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1189scalars. 1437scalars.
1190 1438
1191It touches (reads or writes) all memory pages in the specified 1439It touches (reads or writes) all memory pages in the specified
1192range inside the scalar. All caveats and parameters are the same 1440range inside the scalar. All caveats and parameters are the same
1193as for C<aio_msync>, above, except for flags, which must be either 1441as for C<aio_msync>, above, except for flags, which must be either
1194C<0> (which reads all pages and ensures they are instantiated) or 1442C<0> (which reads all pages and ensures they are instantiated) or
1195C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and 1443C<IO::AIO::MT_MODIFY>, which modifies the memory pages (by reading and
1196writing an octet from it, which dirties the page). 1444writing an octet from it, which dirties the page).
1197 1445
1198=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) 1446=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
1199 1447
1200This is a rather advanced IO::AIO call, which works best on mmap(2)ed 1448This is a rather advanced IO::AIO call, which works best on mmap(2)ed
… …
1219 IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh; 1467 IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
1220 aio_mlock $data; # mlock in background 1468 aio_mlock $data; # mlock in background
1221 1469
1222=item aio_mlockall $flags, $callback->($status) 1470=item aio_mlockall $flags, $callback->($status)
1223 1471
1224Calls the C<mlockall> function with the given C<$flags> (a combination of 1472Calls the C<mlockall> function with the given C<$flags> (a
1225C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>). 1473combination of C<IO::AIO::MCL_CURRENT>, C<IO::AIO::MCL_FUTURE> and
1474C<IO::AIO::MCL_ONFAULT>).
1226 1475
1227On systems that do not implement C<mlockall>, this function returns C<-1> 1476On systems that do not implement C<mlockall>, this function returns C<-1>
1228and sets errno to C<ENOSYS>. 1477and sets errno to C<ENOSYS>. Similarly, flag combinations not supported
1478by the system result in a return value of C<-1> with errno being set to
1479C<EINVAL>.
1229 1480
1230Note that the corresponding C<munlockall> is synchronous and is 1481Note that the corresponding C<munlockall> is synchronous and is
1231documented under L<MISCELLANEOUS FUNCTIONS>. 1482documented under L<MISCELLANEOUS FUNCTIONS>.
1232 1483
1233Example: asynchronously lock all current and future pages into memory. 1484Example: asynchronously lock all current and future pages into memory.
1234 1485
1235 aio_mlockall IO::AIO::MCL_FUTURE; 1486 aio_mlockall IO::AIO::MCL_FUTURE;
1487
1488=item aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
1489
1490Queries the extents of the given file (by calling the Linux C<FIEMAP>
1491ioctl, see L<http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for details). If
1492the ioctl is not available on your OS, then this request will fail with
1493C<ENOSYS>.
1494
1495C<$start> is the starting offset to query extents for, C<$length> is the
1496size of the range to query - if it is C<undef>, then the whole file will
1497be queried.
1498
1499C<$flags> is a combination of flags (C<IO::AIO::FIEMAP_FLAG_SYNC> or
1500C<IO::AIO::FIEMAP_FLAG_XATTR> - C<IO::AIO::FIEMAP_FLAGS_COMPAT> is also
1501exported), and is normally C<0> or C<IO::AIO::FIEMAP_FLAG_SYNC> to query
1502the data portion.
1503
1504C<$count> is the maximum number of extent records to return. If it is
1505C<undef>, then IO::AIO queries all extents of the range. As a very special
1506case, if it is C<0>, then the callback receives the number of extents
1507instead of the extents themselves (which is unreliable, see below).
1508
1509If an error occurs, the callback receives no arguments. The special
1510C<errno> value C<IO::AIO::EBADR> is available to test for flag errors.
1511
1512Otherwise, the callback receives an array reference with extent
1513structures. Each extent structure is an array reference itself, with the
1514following members:
1515
1516 [$logical, $physical, $length, $flags]
1517
1518Flags is any combination of the following flag values (typically either C<0>
1519or C<IO::AIO::FIEMAP_EXTENT_LAST> (1)):
1520
1521C<IO::AIO::FIEMAP_EXTENT_LAST>, C<IO::AIO::FIEMAP_EXTENT_UNKNOWN>,
1522C<IO::AIO::FIEMAP_EXTENT_DELALLOC>, C<IO::AIO::FIEMAP_EXTENT_ENCODED>,
1523C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
1524C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
1525C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
1526C<IO::AIO::FIEMAP_EXTENT_SHARED>.
1527
1528At the time of this writing (Linux 3.2), this request is unreliable unless
1529C<$count> is C<undef>, as the kernel has all sorts of bugs preventing
1530it to return all extents of a range for files with a large number of
1531extents. The code (only) works around all these issues if C<$count> is
1532C<undef>.
1236 1533
1237=item aio_group $callback->(...) 1534=item aio_group $callback->(...)
1238 1535
1239This is a very special aio request: Instead of doing something, it is a 1536This is a very special aio request: Instead of doing something, it is a
1240container for other aio requests, which is useful if you want to bundle 1537container for other aio requests, which is useful if you want to bundle
… …
1304object. This object stores the canonicalised, absolute version of the 1601object. This object stores the canonicalised, absolute version of the
1305path, and on systems that allow it, also a directory file descriptor. 1602path, and on systems that allow it, also a directory file descriptor.
1306 1603
1307Everywhere where a pathname is accepted by IO::AIO (e.g. in C<aio_stat> 1604Everywhere where a pathname is accepted by IO::AIO (e.g. in C<aio_stat>
1308or C<aio_unlink>), one can specify an array reference with an IO::AIO::WD 1605or C<aio_unlink>), one can specify an array reference with an IO::AIO::WD
1309object and a pathname instead. If the pathname is absolute, the 1606object and a pathname instead (or the IO::AIO::WD object alone, which
1607gets interpreted as C<[$wd, "."]>). If the pathname is absolute, the
1310IO::AIO::WD objetc is ignored, otherwise the pathname is resolved relative 1608IO::AIO::WD object is ignored, otherwise the pathname is resolved relative
1311to that IO::AIO::WD object. 1609to that IO::AIO::WD object.
1312 1610
1313For example, to get a wd object for F</etc> and then stat F<passwd> 1611For example, to get a wd object for F</etc> and then stat F<passwd>
1314inside, you would write: 1612inside, you would write:
1315 1613
… …
1323 aio_stat [$etcdir, "passwd"], sub { 1621 aio_stat [$etcdir, "passwd"], sub {
1324 # yay 1622 # yay
1325 }; 1623 };
1326 }; 1624 };
1327 1625
1626The fact that C<aio_wd> is a request and not a normal function shows that
1328This shows that creating an IO::AIO::WD object is itself a potentially 1627creating an IO::AIO::WD object is itself a potentially blocking operation,
1329blocking operation, which is why it is done asynchronously. 1628which is why it is done asynchronously.
1629
1630To stat the directory obtained with C<aio_wd> above, one could write
1631either of the following three request calls:
1632
1633 aio_lstat "/etc" , sub { ... # pathname as normal string
1634 aio_lstat [$wd, "."], sub { ... # "." relative to $wd (i.e. $wd itself)
1635 aio_lstat $wd , sub { ... # shorthand for the previous
1330 1636
1331As with normal pathnames, IO::AIO keeps a copy of the working directory 1637As with normal pathnames, IO::AIO keeps a copy of the working directory
1332object and the pathname string, so you could write the following without 1638object and the pathname string, so you could write the following without
1333causing any issues due to C<$path> getting reused: 1639causing any issues due to C<$path> getting reused:
1334 1640
… …
1344There are some caveats: when directories get renamed (or deleted), the 1650There are some caveats: when directories get renamed (or deleted), the
1345pathname string doesn't change, so will point to the new directory (or 1651pathname string doesn't change, so will point to the new directory (or
1346nowhere at all), while the directory fd, if available on the system, 1652nowhere at all), while the directory fd, if available on the system,
1347will still point to the original directory. Most functions accepting a 1653will still point to the original directory. Most functions accepting a
1348pathname will use the directory fd on newer systems, and the string on 1654pathname will use the directory fd on newer systems, and the string on
1349older systems. Some functions (such as realpath) will always rely on the 1655older systems. Some functions (such as C<aio_realpath>) will always rely on
1350string form of the pathname. 1656the string form of the pathname.
1351 1657
1352So this fucntionality is mainly useful to get some protection against 1658So this functionality is mainly useful to get some protection against
1353C<chdir>, to easily get an absolute path out of a relative path for future 1659C<chdir>, to easily get an absolute path out of a relative path for future
1354reference, and to speed up doing many operations in the same directory 1660reference, and to speed up doing many operations in the same directory
1355(e.g. when stat'ing all files in a directory). 1661(e.g. when stat'ing all files in a directory).
1356 1662
1357The following functions implement this working directory abstraction: 1663The following functions implement this working directory abstraction:
… …
1370passing C<undef> as working directory component of a pathname fails the 1676passing C<undef> as working directory component of a pathname fails the
1371request with C<ENOENT>, there is often no need for error checking in the 1677request with C<ENOENT>, there is often no need for error checking in the
1372C<aio_wd> callback, as future requests using the value will fail in the 1678C<aio_wd> callback, as future requests using the value will fail in the
1373expected way. 1679expected way.
1374 1680
1375If this call isn't available because your OS lacks it or it couldn't be
1376detected, it will be emulated by calling C<fsync> instead.
1377
1378=item IO::AIO::CWD 1681=item IO::AIO::CWD
1379 1682
1380This is a compiletime constant (object) that represents the process 1683This is a compiletime constant (object) that represents the process
1381current working directory. 1684current working directory.
1382 1685
1383Specifying this object as working directory object for a pathname is as 1686Specifying this object as working directory object for a pathname is as if
1384if the pathname would be specified directly, without a directory object, 1687the pathname would be specified directly, without a directory object. For
1385e.g., these calls are functionally identical: 1688example, these calls are functionally identical:
1386 1689
1387 aio_stat "somefile", sub { ... }; 1690 aio_stat "somefile", sub { ... };
1388 aio_stat [IO::AIO::CWD, "somefile"], sub { ... }; 1691 aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
1389 1692
1390=back 1693=back
1391 1694
1695To recover the path associated with an IO::AIO::WD object, you can use
1696C<aio_realpath>:
1697
1698 aio_realpath $wd, sub {
1699 warn "path is $_[0]\n";
1700 };
1701
1702Currently, C<aio_statvfs> always, and C<aio_rename> and C<aio_rmdir>
1703sometimes, fall back to using an absolue path.
1392 1704
1393=head2 IO::AIO::REQ CLASS 1705=head2 IO::AIO::REQ CLASS
1394 1706
1395All non-aggregate C<aio_*> functions return an object of this class when 1707All non-aggregate C<aio_*> functions return an object of this class when
1396called in non-void context. 1708called in non-void context.
… …
1557The default value for the limit is C<0>, but note that setting a feeder 1869The default value for the limit is C<0>, but note that setting a feeder
1558automatically bumps it up to C<2>. 1870automatically bumps it up to C<2>.
1559 1871
1560=back 1872=back
1561 1873
1874
1562=head2 SUPPORT FUNCTIONS 1875=head2 SUPPORT FUNCTIONS
1563 1876
1564=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION 1877=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
1565 1878
1566=over 4 1879=over 4
… …
1574 1887
1575See C<poll_cb> for an example. 1888See C<poll_cb> for an example.
1576 1889
1577=item IO::AIO::poll_cb 1890=item IO::AIO::poll_cb
1578 1891
1579Process some outstanding events on the result pipe. You have to call 1892Process some requests that have reached the result phase (i.e. they have
1893been executed but the results are not yet reported). You have to call
1894this "regularly" to finish outstanding requests.
1895
1580this regularly. Returns C<0> if all events could be processed (or there 1896Returns C<0> if all events could be processed (or there were no
1581were no events to process), or C<-1> if it returned earlier for whatever 1897events to process), or C<-1> if it returned earlier for whatever
1582reason. Returns immediately when no events are outstanding. The amount of 1898reason. Returns immediately when no events are outstanding. The amount
1583events processed depends on the settings of C<IO::AIO::max_poll_req> and 1899of events processed depends on the settings of C<IO::AIO::max_poll_req>,
1584C<IO::AIO::max_poll_time>. 1900C<IO::AIO::max_poll_time> and C<IO::AIO::max_outstanding>.
1585 1901
1586If not all requests were processed for whatever reason, the filehandle 1902If not all requests were processed for whatever reason, the poll file
1587will still be ready when C<poll_cb> returns, so normally you don't have to 1903descriptor will still be ready when C<poll_cb> returns, so normally you
1588do anything special to have it called later. 1904don't have to do anything special to have it called later.
1589 1905
1590Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes 1906Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
1591ready, it can be beneficial to call this function from loops which submit 1907ready, it can be beneficial to call this function from loops which submit
1592a lot of requests, to make sure the results get processed when they become 1908a lot of requests, to make sure the results get processed when they become
1593available and not just when the loop is finished and the event loop takes 1909available and not just when the loop is finished and the event loop takes
… …
1602 poll => 'r', async => 1, 1918 poll => 'r', async => 1,
1603 cb => \&IO::AIO::poll_cb); 1919 cb => \&IO::AIO::poll_cb);
1604 1920
1605=item IO::AIO::poll_wait 1921=item IO::AIO::poll_wait
1606 1922
1607If there are any outstanding requests and none of them in the result 1923Wait until either at least one request is in the result phase or no
1608phase, wait till the result filehandle becomes ready for reading (simply 1924requests are outstanding anymore.
1609does a C<select> on the filehandle. This is useful if you want to 1925
1610synchronously wait for some requests to finish). 1926This is useful if you want to synchronously wait for some requests to
1927become ready, without actually handling them.
1611 1928
1612See C<nreqs> for an example. 1929See C<nreqs> for an example.
1613 1930
1614=item IO::AIO::poll 1931=item IO::AIO::poll
1615 1932
… …
1626 1943
1627Strictly equivalent to: 1944Strictly equivalent to:
1628 1945
1629 IO::AIO::poll_wait, IO::AIO::poll_cb 1946 IO::AIO::poll_wait, IO::AIO::poll_cb
1630 while IO::AIO::nreqs; 1947 while IO::AIO::nreqs;
1948
1949This function can be useful at program aborts, to make sure outstanding
1950I/O has been done (C<IO::AIO> uses an C<END> block which already calls
1951this function on normal exits), or when you are merely using C<IO::AIO>
1952for its more advanced functions, rather than for async I/O, e.g.:
1953
1954 my ($dirs, $nondirs);
1955 IO::AIO::aio_scandir "/tmp", 0, sub { ($dirs, $nondirs) = @_ };
1956 IO::AIO::flush;
1957 # $dirs, $nondirs are now set
1631 1958
1632=item IO::AIO::max_poll_reqs $nreqs 1959=item IO::AIO::max_poll_reqs $nreqs
1633 1960
1634=item IO::AIO::max_poll_time $seconds 1961=item IO::AIO::max_poll_time $seconds
1635 1962
… …
1662 poll => 'r', nice => 1, 1989 poll => 'r', nice => 1,
1663 cb => &IO::AIO::poll_cb); 1990 cb => &IO::AIO::poll_cb);
1664 1991
1665=back 1992=back
1666 1993
1994
1667=head3 CONTROLLING THE NUMBER OF THREADS 1995=head3 CONTROLLING THE NUMBER OF THREADS
1668 1996
1669=over 1997=over
1670 1998
1671=item IO::AIO::min_parallel $nthreads 1999=item IO::AIO::min_parallel $nthreads
… …
1736 2064
1737This is a very bad function to use in interactive programs because it 2065This is a very bad function to use in interactive programs because it
1738blocks, and a bad way to reduce concurrency because it is inexact: Better 2066blocks, and a bad way to reduce concurrency because it is inexact: Better
1739use an C<aio_group> together with a feed callback. 2067use an C<aio_group> together with a feed callback.
1740 2068
1741It's main use is in scripts without an event loop - when you want to stat 2069Its main use is in scripts without an event loop - when you want to stat
1742a lot of files, you can write somehting like this: 2070a lot of files, you can write something like this:
1743 2071
1744 IO::AIO::max_outstanding 32; 2072 IO::AIO::max_outstanding 32;
1745 2073
1746 for my $path (...) { 2074 for my $path (...) {
1747 aio_stat $path , ...; 2075 aio_stat $path , ...;
… …
1758The default value for C<max_outstanding> is very large, so there is no 2086The default value for C<max_outstanding> is very large, so there is no
1759practical limit on the number of outstanding requests. 2087practical limit on the number of outstanding requests.
1760 2088
1761=back 2089=back
1762 2090
2091
1763=head3 STATISTICAL INFORMATION 2092=head3 STATISTICAL INFORMATION
1764 2093
1765=over 2094=over
1766 2095
1767=item IO::AIO::nreqs 2096=item IO::AIO::nreqs
… …
1784Returns the number of requests currently in the pending state (executed, 2113Returns the number of requests currently in the pending state (executed,
1785but not yet processed by poll_cb). 2114but not yet processed by poll_cb).
1786 2115
1787=back 2116=back
1788 2117
2118
2119=head3 SUBSECOND STAT TIME ACCESS
2120
2121Both C<aio_stat>/C<aio_lstat> and perl's C<stat>/C<lstat> functions can
2122generally find access/modification and change times with subsecond time
2123accuracy of the system supports it, but perl's built-in functions only
2124return the integer part.
2125
2126The following functions return the timestamps of the most recent
2127stat with subsecond precision on most systems and work both after
2128C<aio_stat>/C<aio_lstat> and perl's C<stat>/C<lstat> calls. Their return
2129value is only meaningful after a successful C<stat>/C<lstat> call, or
2130during/after a successful C<aio_stat>/C<aio_lstat> callback.
2131
2132This is similar to the L<Time::HiRes> C<stat> functions, but can return
2133full resolution without rounding and work with standard perl C<stat>,
2134alleviating the need to call the special C<Time::HiRes> functions, which
2135do not act like their perl counterparts.
2136
2137On operating systems or file systems where subsecond time resolution is
2138not supported or could not be detected, a fractional part of C<0> is
2139returned, so it is always safe to call these functions.
2140
2141=over 4
2142
2143=item $seconds = IO::AIO::st_atime, IO::AIO::st_mtime, IO::AIO::st_ctime, IO::AIO::st_btime
2144
2145Return the access, modication, change or birth time, respectively,
2146including fractional part. Due to the limited precision of floating point,
2147the accuracy on most platforms is only a bit better than milliseconds
2148for times around now - see the I<nsec> function family, below, for full
2149accuracy.
2150
2151File birth time is only available when the OS and perl support it (on
2152FreeBSD and NetBSD at the time of this writing, although support is
2153adaptive, so if your OS/perl gains support, IO::AIO can take advantage of
2154it). On systems where it isn't available, C<0> is currently returned, but
2155this might change to C<undef> in a future version.
2156
2157=item ($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtime
2158
2159Returns access, modification, change and birth time all in one go, and
2160maybe more times in the future version.
2161
2162=item $nanoseconds = IO::AIO::st_atimensec, IO::AIO::st_mtimensec, IO::AIO::st_ctimensec, IO::AIO::st_btimensec
2163
2164Return the fractional access, modifcation, change or birth time, in nanoseconds,
2165as an integer in the range C<0> to C<999999999>.
2166
2167Note that no accessors are provided for access, modification and
2168change times - you need to get those from C<stat _> if required (C<int
2169IO::AIO::st_atime> and so on will I<not> generally give you the correct
2170value).
2171
2172=item $seconds = IO::AIO::st_btimesec
2173
2174The (integral) seconds part of the file birth time, if available.
2175
2176=item ($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtimensec
2177
2178Like the functions above, but returns all four times in one go (and maybe
2179more in future versions).
2180
2181=item $counter = IO::AIO::st_gen
2182
2183Returns the generation counter (in practice this is just a random number)
2184of the file. This is only available on platforms which have this member in
2185their C<struct stat> (most BSDs at the time of this writing) and generally
2186only to the root usert. If unsupported, C<0> is returned, but this might
2187change to C<undef> in a future version.
2188
2189=back
2190
2191Example: print the high resolution modification time of F</etc>, using
2192C<stat>, and C<IO::AIO::aio_stat>.
2193
2194 if (stat "/etc") {
2195 printf "stat(/etc) mtime: %f\n", IO::AIO::st_mtime;
2196 }
2197
2198 IO::AIO::aio_stat "/etc", sub {
2199 $_[0]
2200 and return;
2201
2202 printf "aio_stat(/etc) mtime: %d.%09d\n", (stat _)[9], IO::AIO::st_mtimensec;
2203 };
2204
2205 IO::AIO::flush;
2206
2207Output of the awbove on my system, showing reduced and full accuracy:
2208
2209 stat(/etc) mtime: 1534043702.020808
2210 aio_stat(/etc) mtime: 1534043702.020807792
2211
2212
1789=head3 MISCELLANEOUS FUNCTIONS 2213=head3 MISCELLANEOUS FUNCTIONS
1790 2214
1791IO::AIO implements some functions that might be useful, but are not 2215IO::AIO implements some functions that are useful when you want to use
1792asynchronous. 2216some "Advanced I/O" function not available to in Perl, without going the
2217"Asynchronous I/O" route. Many of these have an asynchronous C<aio_*>
2218counterpart.
1793 2219
1794=over 4 2220=over 4
2221
2222=item $numfd = IO::AIO::get_fdlimit
2223
2224This function is I<EXPERIMENTAL> and subject to change.
2225
2226Tries to find the current file descriptor limit and returns it, or
2227C<undef> and sets C<$!> in case of an error. The limit is one larger than
2228the highest valid file descriptor number.
2229
2230=item IO::AIO::min_fdlimit [$numfd]
2231
2232This function is I<EXPERIMENTAL> and subject to change.
2233
2234Try to increase the current file descriptor limit(s) to at least C<$numfd>
2235by changing the soft or hard file descriptor resource limit. If C<$numfd>
2236is missing, it will try to set a very high limit, although this is not
2237recommended when you know the actual minimum that you require.
2238
2239If the limit cannot be raised enough, the function makes a best-effort
2240attempt to increase the limit as much as possible, using various
2241tricks, while still failing. You can query the resulting limit using
2242C<IO::AIO::get_fdlimit>.
2243
2244If an error occurs, returns C<undef> and sets C<$!>, otherwise returns
2245true.
1795 2246
1796=item IO::AIO::sendfile $ofh, $ifh, $offset, $count 2247=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1797 2248
1798Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>, 2249Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
1799but is blocking (this makes most sense if you know the input data is 2250but is blocking (this makes most sense if you know the input data is
… …
1816=item IO::AIO::madvise $scalar, $offset, $len, $advice 2267=item IO::AIO::madvise $scalar, $offset, $len, $advice
1817 2268
1818Simply calls the C<posix_madvise> function (see its 2269Simply calls the C<posix_madvise> function (see its
1819manpage for details). The following advice constants are 2270manpage for details). The following advice constants are
1820available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>, 2271available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
1821C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>. 2272C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>,
2273C<IO::AIO::MADV_DONTNEED>.
2274
2275If C<$offset> is negative, counts from the end. If C<$length> is negative,
2276the remaining length of the C<$scalar> is used. If possible, C<$length>
2277will be reduced to fit into the C<$scalar>.
1822 2278
1823On systems that do not implement C<posix_madvise>, this function returns 2279On systems that do not implement C<posix_madvise>, this function returns
1824ENOSYS, otherwise the return value of C<posix_madvise>. 2280ENOSYS, otherwise the return value of C<posix_madvise>.
1825 2281
1826=item IO::AIO::mprotect $scalar, $offset, $len, $protect 2282=item IO::AIO::mprotect $scalar, $offset, $len, $protect
… …
1828Simply calls the C<mprotect> function on the preferably AIO::mmap'ed 2284Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
1829$scalar (see its manpage for details). The following protect 2285$scalar (see its manpage for details). The following protect
1830constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>, 2286constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
1831C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>. 2287C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
1832 2288
2289If C<$offset> is negative, counts from the end. If C<$length> is negative,
2290the remaining length of the C<$scalar> is used. If possible, C<$length>
2291will be reduced to fit into the C<$scalar>.
2292
1833On systems that do not implement C<mprotect>, this function returns 2293On systems that do not implement C<mprotect>, this function returns
1834ENOSYS, otherwise the return value of C<mprotect>. 2294ENOSYS, otherwise the return value of C<mprotect>.
1835 2295
1836=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset] 2296=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1837 2297
1838Memory-maps a file (or anonymous memory range) and attaches it to the 2298Memory-maps a file (or anonymous memory range) and attaches it to the
1839given C<$scalar>, which will act like a string scalar. 2299given C<$scalar>, which will act like a string scalar. Returns true on
2300success, and false otherwise.
1840 2301
2302The scalar must exist, but its contents do not matter - this means you
2303cannot use a nonexistant array or hash element. When in doubt, C<undef>
2304the scalar first.
2305
1841The only operations allowed on the scalar are C<substr>/C<vec> that don't 2306The only operations allowed on the mmapped scalar are C<substr>/C<vec>,
1842change the string length, and most read-only operations such as copying it 2307which don't change the string length, and most read-only operations such
1843or searching it with regexes and so on. 2308as copying it or searching it with regexes and so on.
1844 2309
1845Anything else is unsafe and will, at best, result in memory leaks. 2310Anything else is unsafe and will, at best, result in memory leaks.
1846 2311
1847The memory map associated with the C<$scalar> is automatically removed 2312The memory map associated with the C<$scalar> is automatically removed
1848when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or 2313when the C<$scalar> is undef'd or destroyed, or when the C<IO::AIO::mmap>
1849C<IO::AIO::munmap> functions are called. 2314or C<IO::AIO::munmap> functions are called on it.
1850 2315
1851This calls the C<mmap>(2) function internally. See your system's manual 2316This calls the C<mmap>(2) function internally. See your system's manual
1852page for details on the C<$length>, C<$prot> and C<$flags> parameters. 2317page for details on the C<$length>, C<$prot> and C<$flags> parameters.
1853 2318
1854The C<$length> must be larger than zero and smaller than the actual 2319The C<$length> must be larger than zero and smaller than the actual
1855filesize. 2320filesize.
1856 2321
1857C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>, 2322C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
1858C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>, 2323C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
1859 2324
1860C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or 2325C<$flags> can be a combination of
1861C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when 2326C<IO::AIO::MAP_SHARED> or
1862not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS> 2327C<IO::AIO::MAP_PRIVATE>,
2328or a number of system-specific flags (when not available, the are C<0>):
1863(which is set to C<MAP_ANON> if your system only provides this 2329C<IO::AIO::MAP_ANONYMOUS> (which is set to C<MAP_ANON> if your system only provides this constant),
1864constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>, 2330C<IO::AIO::MAP_LOCKED>,
1865C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or 2331C<IO::AIO::MAP_NORESERVE>,
2332C<IO::AIO::MAP_POPULATE>,
1866C<IO::AIO::MAP_NONBLOCK> 2333C<IO::AIO::MAP_NONBLOCK>,
2334C<IO::AIO::MAP_FIXED>,
2335C<IO::AIO::MAP_GROWSDOWN>,
2336C<IO::AIO::MAP_32BIT>,
2337C<IO::AIO::MAP_HUGETLB> or
2338C<IO::AIO::MAP_STACK>.
1867 2339
1868If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed. 2340If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
1869 2341
1870C<$offset> is the offset from the start of the file - it generally must be 2342C<$offset> is the offset from the start of the file - it generally must be
1871a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>. 2343a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
… …
1885 2357
1886=item IO::AIO::munmap $scalar 2358=item IO::AIO::munmap $scalar
1887 2359
1888Removes a previous mmap and undefines the C<$scalar>. 2360Removes a previous mmap and undefines the C<$scalar>.
1889 2361
2362=item IO::AIO::mremap $scalar, $new_length, $flags = MREMAP_MAYMOVE[, $new_address = 0]
2363
2364Calls the Linux-specific mremap(2) system call. The C<$scalar> must have
2365been mapped by C<IO::AIO::mmap>, and C<$flags> must currently either be
2366C<0> or C<IO::AIO::MREMAP_MAYMOVE>.
2367
2368Returns true if successful, and false otherwise. If the underlying mmapped
2369region has changed address, then the true value has the numerical value
2370C<1>, otherwise it has the numerical value C<0>:
2371
2372 my $success = IO::AIO::mremap $mmapped, 8192, IO::AIO::MREMAP_MAYMOVE
2373 or die "mremap: $!";
2374
2375 if ($success*1) {
2376 warn "scalar has chanegd address in memory\n";
2377 }
2378
2379C<IO::AIO::MREMAP_FIXED> and the C<$new_address> argument are currently
2380implemented, but not supported and might go away in a future version.
2381
2382On systems where this call is not supported or is not emulated, this call
2383returns falls and sets C<$!> to C<ENOSYS>.
2384
2385=item IO::AIO::mlockall $flags
2386
2387Calls the C<eio_mlockall_sync> function, which is like C<aio_mlockall>,
2388but is blocking.
2389
1890=item IO::AIO::munlock $scalar, $offset = 0, $length = undef 2390=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
1891 2391
1892Calls the C<munlock> function, undoing the effects of a previous 2392Calls the C<munlock> function, undoing the effects of a previous
1893C<aio_mlock> call (see its description for details). 2393C<aio_mlock> call (see its description for details).
1894 2394
… …
1896 2396
1897Calls the C<munlockall> function. 2397Calls the C<munlockall> function.
1898 2398
1899On systems that do not implement C<munlockall>, this function returns 2399On systems that do not implement C<munlockall>, this function returns
1900ENOSYS, otherwise the return value of C<munlockall>. 2400ENOSYS, otherwise the return value of C<munlockall>.
2401
2402=item IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
2403
2404Calls the GNU/Linux C<splice(2)> syscall, if available. If C<$r_off> or
2405C<$w_off> are C<undef>, then C<NULL> is passed for these, otherwise they
2406should be the file offset.
2407
2408C<$r_fh> and C<$w_fh> should not refer to the same file, as splice might
2409silently corrupt the data in this case.
2410
2411The following symbol flag values are available: C<IO::AIO::SPLICE_F_MOVE>,
2412C<IO::AIO::SPLICE_F_NONBLOCK>, C<IO::AIO::SPLICE_F_MORE> and
2413C<IO::AIO::SPLICE_F_GIFT>.
2414
2415See the C<splice(2)> manpage for details.
2416
2417=item IO::AIO::tee $r_fh, $w_fh, $length, $flags
2418
2419Calls the GNU/Linux C<tee(2)> syscall, see its manpage and the
2420description for C<IO::AIO::splice> above for details.
2421
2422=item $actual_size = IO::AIO::pipesize $r_fh[, $new_size]
2423
2424Attempts to query or change the pipe buffer size. Obviously works only
2425on pipes, and currently works only on GNU/Linux systems, and fails with
2426C<-1>/C<ENOSYS> everywhere else. If anybody knows how to influence pipe buffer
2427size on other systems, drop me a note.
2428
2429=item ($rfh, $wfh) = IO::AIO::pipe2 [$flags]
2430
2431This is a direct interface to the Linux L<pipe2(2)> system call. If
2432C<$flags> is missing or C<0>, then this should be the same as a call to
2433perl's built-in C<pipe> function and create a new pipe, and works on
2434systems that lack the pipe2 syscall. On win32, this case invokes C<_pipe
2435(..., 4096, O_BINARY)>.
2436
2437If C<$flags> is non-zero, it tries to invoke the pipe2 system call with
2438the given flags (Linux 2.6.27, glibc 2.9).
2439
2440On success, the read and write file handles are returned.
2441
2442On error, nothing will be returned. If the pipe2 syscall is missing and
2443C<$flags> is non-zero, fails with C<ENOSYS>.
2444
2445Please refer to L<pipe2(2)> for more info on the C<$flags>, but at the
2446time of this writing, C<IO::AIO::O_CLOEXEC>, C<IO::AIO::O_NONBLOCK> and
2447C<IO::AIO::O_DIRECT> (Linux 3.4, for packet-based pipes) were supported.
2448
2449Example: create a pipe race-free w.r.t. threads and fork:
2450
2451 my ($rfh, $wfh) = IO::AIO::pipe2 IO::AIO::O_CLOEXEC
2452 or die "pipe2: $!\n";
2453
2454=item $fh = IO::AIO::memfd_create $pathname[, $flags]
2455
2456This is a direct interface to the Linux L<memfd_create(2)> system
2457call. The (unhelpful) default for C<$flags> is C<0>, but your default
2458should be C<IO::AIO::MFD_CLOEXEC>.
2459
2460On success, the new memfd filehandle is returned, otherwise returns
2461C<undef>. If the memfd_create syscall is missing, fails with C<ENOSYS>.
2462
2463Please refer to L<memfd_create(2)> for more info on this call.
2464
2465The following C<$flags> values are available: C<IO::AIO::MFD_CLOEXEC>,
2466C<IO::AIO::MFD_ALLOW_SEALING> and C<IO::AIO::MFD_HUGETLB>.
2467
2468Example: create a new memfd.
2469
2470 my $fh = IO::AIO::memfd_create "somenameforprocfd", IO::AIO::MFD_CLOEXEC
2471 or die "m,emfd_create: $!\n";
2472=item $fh = IO::AIO::eventfd [$initval, [$flags]]
2473
2474This is a direct interface to the Linux L<eventfd(2)> system call. The
2475(unhelpful) defaults for C<$initval> and C<$flags> are C<0> for both.
2476
2477On success, the new eventfd filehandle is returned, otherwise returns
2478C<undef>. If the eventfd syscall is missing, fails with C<ENOSYS>.
2479
2480Please refer to L<eventfd(2)> for more info on this call.
2481
2482The following symbol flag values are available: C<IO::AIO::EFD_CLOEXEC>,
2483C<IO::AIO::EFD_NONBLOCK> and C<IO::AIO::EFD_SEMAPHORE> (Linux 2.6.30).
2484
2485Example: create a new eventfd filehandle:
2486
2487 $fh = IO::AIO::eventfd 0, IO::AIO::EFD_CLOEXEC
2488 or die "eventfd: $!\n";
2489
2490=item $fh = IO::AIO::timerfd_create $clockid[, $flags]
2491
2492This is a direct interface to the Linux L<timerfd_create(2)> system
2493call. The (unhelpful) default for C<$flags> is C<0>, but your default
2494should be C<IO::AIO::TFD_CLOEXEC>.
2495
2496On success, the new timerfd filehandle is returned, otherwise returns
2497C<undef>. If the timerfd_create syscall is missing, fails with C<ENOSYS>.
2498
2499Please refer to L<timerfd_create(2)> for more info on this call.
2500
2501The following C<$clockid> values are
2502available: C<IO::AIO::CLOCK_REALTIME>, C<IO::AIO::CLOCK_MONOTONIC>
2503C<IO::AIO::CLOCK_CLOCK_BOOTTIME> (Linux 3.15)
2504C<IO::AIO::CLOCK_CLOCK_REALTIME_ALARM> (Linux 3.11) and
2505C<IO::AIO::CLOCK_CLOCK_BOOTTIME_ALARM> (Linux 3.11).
2506
2507The following C<$flags> values are available (Linux
25082.6.27): C<IO::AIO::TFD_NONBLOCK> and C<IO::AIO::TFD_CLOEXEC>.
2509
2510Example: create a new timerfd and set it to one-second repeated alarms,
2511then wait for two alarms:
2512
2513 my $fh = IO::AIO::timerfd_create IO::AIO::CLOCK_BOOTTIME, IO::AIO::TFD_CLOEXEC
2514 or die "timerfd_create: $!\n";
2515
2516 defined IO::AIO::timerfd_settime $fh, 0, 1, 1
2517 or die "timerfd_settime: $!\n";
2518
2519 for (1..2) {
2520 8 == sysread $fh, my $buf, 8
2521 or die "timerfd read failure\n";
2522
2523 printf "number of expirations (likely 1): %d\n",
2524 unpack "Q", $buf;
2525 }
2526
2527=item ($cur_interval, $cur_value) = IO::AIO::timerfd_settime $fh, $flags, $new_interval, $nbw_value
2528
2529This is a direct interface to the Linux L<timerfd_settime(2)> system
2530call. Please refer to its manpage for more info on this call.
2531
2532The new itimerspec is specified using two (possibly fractional) second
2533values, C<$new_interval> and C<$new_value>).
2534
2535On success, the current interval and value are returned (as per
2536C<timerfd_gettime>). On failure, the empty list is returned.
2537
2538The following C<$flags> values are
2539available: C<IO::AIO::TFD_TIMER_ABSTIME> and
2540C<IO::AIO::TFD_TIMER_CANCEL_ON_SET>.
2541
2542See C<IO::AIO::timerfd_create> for a full example.
2543
2544=item ($cur_interval, $cur_value) = IO::AIO::timerfd_gettime $fh
2545
2546This is a direct interface to the Linux L<timerfd_gettime(2)> system
2547call. Please refer to its manpage for more info on this call.
2548
2549On success, returns the current values of interval and value for the given
2550timerfd (as potentially fractional second values). On failure, the empty
2551list is returned.
1901 2552
1902=back 2553=back
1903 2554
1904=cut 2555=cut
1905 2556
… …
1971the process will result in undefined behaviour. Calling it at any time 2622the process will result in undefined behaviour. Calling it at any time
1972will also result in any undefined (by POSIX) behaviour. 2623will also result in any undefined (by POSIX) behaviour.
1973 2624
1974=back 2625=back
1975 2626
2627=head2 LINUX-SPECIFIC CALLS
2628
2629When a call is documented as "linux-specific" then this means it
2630originated on GNU/Linux. C<IO::AIO> will usually try to autodetect the
2631availability and compatibility of such calls regardless of the platform
2632it is compiled on, so platforms such as FreeBSD which often implement
2633these calls will work. When in doubt, call them and see if they fail wth
2634C<ENOSYS>.
2635
1976=head2 MEMORY USAGE 2636=head2 MEMORY USAGE
1977 2637
1978Per-request usage: 2638Per-request usage:
1979 2639
1980Each aio request uses - depending on your architecture - around 100-200 2640Each aio request uses - depending on your architecture - around 100-200
… …
1992temporary buffers, and each thread requires a stack and other data 2652temporary buffers, and each thread requires a stack and other data
1993structures (usually around 16k-128k, depending on the OS). 2653structures (usually around 16k-128k, depending on the OS).
1994 2654
1995=head1 KNOWN BUGS 2655=head1 KNOWN BUGS
1996 2656
1997Known bugs will be fixed in the next release. 2657Known bugs will be fixed in the next release :)
2658
2659=head1 KNOWN ISSUES
2660
2661Calls that try to "import" foreign memory areas (such as C<IO::AIO::mmap>
2662or C<IO::AIO::aio_slurp>) do not work with generic lvalues, such as
2663non-created hash slots or other scalars I didn't think of. It's best to
2664avoid such and either use scalar variables or making sure that the scalar
2665exists (e.g. by storing C<undef>) and isn't "funny" (e.g. tied).
2666
2667I am not sure anything can be done about this, so this is considered a
2668known issue, rather than a bug.
1998 2669
1999=head1 SEE ALSO 2670=head1 SEE ALSO
2000 2671
2001L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a 2672L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
2002more natural syntax. 2673more natural syntax and L<IO::FDPass> for file descriptor passing.
2003 2674
2004=head1 AUTHOR 2675=head1 AUTHOR
2005 2676
2006 Marc Lehmann <schmorp@schmorp.de> 2677 Marc Lehmann <schmorp@schmorp.de>
2007 http://home.schmorp.de/ 2678 http://home.schmorp.de/

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