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Revision 1.67 by root, Tue Jul 27 07:58:38 2021 UTC

1NAME 1NAME
2 IO::AIO - Asynchronous Input/Output 2 IO::AIO - Asynchronous/Advanced Input/Output
3 3
4SYNOPSIS 4SYNOPSIS
5 use IO::AIO; 5 use IO::AIO;
6 6
7 aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub { 7 aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
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55 not well-supported or restricted (GNU/Linux doesn't allow them on normal 55 not well-supported or restricted (GNU/Linux doesn't allow them on normal
56 files currently, for example), and they would only support aio_read and 56 files currently, for example), and they would only support aio_read and
57 aio_write, so the remaining functionality would have to be implemented 57 aio_write, so the remaining functionality would have to be implemented
58 using threads anyway. 58 using threads anyway.
59 59
60 In addition to asynchronous I/O, this module also exports some rather
61 arcane interfaces, such as "madvise" or linux's "splice" system call,
62 which is why the "A" in "AIO" can also mean *advanced*.
63
60 Although the module will work in the presence of other (Perl-) threads, 64 Although the module will work in the presence of other (Perl-) threads,
61 it is currently not reentrant in any way, so use appropriate locking 65 it is currently not reentrant in any way, so use appropriate locking
62 yourself, always call "poll_cb" from within the same thread, or never 66 yourself, always call "poll_cb" from within the same thread, or never
63 call "poll_cb" (or other "aio_" functions) recursively. 67 call "poll_cb" (or other "aio_" functions) recursively.
64 68
65 EXAMPLE 69 EXAMPLE
66 This is a simple example that uses the EV module and loads /etc/passwd 70 This is a simple example that uses the EV module and loads /etc/passwd
67 asynchronously: 71 asynchronously:
68 72
69 use Fcntl;
70 use EV; 73 use EV;
71 use IO::AIO; 74 use IO::AIO;
72 75
73 # register the IO::AIO callback with EV 76 # register the IO::AIO callback with EV
74 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb; 77 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
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91 94
92 # file contents now in $contents 95 # file contents now in $contents
93 print $contents; 96 print $contents;
94 97
95 # exit event loop and program 98 # exit event loop and program
96 EV::unloop; 99 EV::break;
97 }; 100 };
98 }; 101 };
99 102
100 # possibly queue up other requests, or open GUI windows, 103 # possibly queue up other requests, or open GUI windows,
101 # check for sockets etc. etc. 104 # check for sockets etc. etc.
102 105
103 # process events as long as there are some: 106 # process events as long as there are some:
104 EV::loop; 107 EV::run;
105 108
106REQUEST ANATOMY AND LIFETIME 109REQUEST ANATOMY AND LIFETIME
107 Every "aio_*" function creates a request. which is a C data structure 110 Every "aio_*" function creates a request. which is a C data structure
108 not directly visible to Perl. 111 not directly visible to Perl.
109 112
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146 the actual aio request is severed and calling its methods will 149 the actual aio request is severed and calling its methods will
147 either do nothing or result in a runtime error). 150 either do nothing or result in a runtime error).
148 151
149FUNCTIONS 152FUNCTIONS
150 QUICK OVERVIEW 153 QUICK OVERVIEW
151 This section simply lists the prototypes of the most important functions 154 This section simply lists the prototypes most of the functions for quick
152 for quick reference. See the following sections for function-by-function 155 reference. See the following sections for function-by-function
153 documentation. 156 documentation.
154 157
155 aio_wd $pathname, $callback->($wd) 158 aio_wd $pathname, $callback->($wd)
156 aio_open $pathname, $flags, $mode, $callback->($fh) 159 aio_open $pathname, $flags, $mode, $callback->($fh)
157 aio_close $fh, $callback->($status) 160 aio_close $fh, $callback->($status)
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165 aio_statvfs $fh_or_path, $callback->($statvfs) 168 aio_statvfs $fh_or_path, $callback->($statvfs)
166 aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 169 aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
167 aio_chown $fh_or_path, $uid, $gid, $callback->($status) 170 aio_chown $fh_or_path, $uid, $gid, $callback->($status)
168 aio_chmod $fh_or_path, $mode, $callback->($status) 171 aio_chmod $fh_or_path, $mode, $callback->($status)
169 aio_truncate $fh_or_path, $offset, $callback->($status) 172 aio_truncate $fh_or_path, $offset, $callback->($status)
173 aio_allocate $fh, $mode, $offset, $len, $callback->($status)
174 aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
170 aio_unlink $pathname, $callback->($status) 175 aio_unlink $pathname, $callback->($status)
171 aio_mknod $pathname, $mode, $dev, $callback->($status) 176 aio_mknod $pathname, $mode, $dev, $callback->($status)
172 aio_link $srcpath, $dstpath, $callback->($status) 177 aio_link $srcpath, $dstpath, $callback->($status)
173 aio_symlink $srcpath, $dstpath, $callback->($status) 178 aio_symlink $srcpath, $dstpath, $callback->($status)
174 aio_readlink $pathname, $callback->($link) 179 aio_readlink $pathname, $callback->($link)
175 aio_realpath $pathname, $callback->($link) 180 aio_realpath $pathname, $callback->($path)
176 aio_rename $srcpath, $dstpath, $callback->($status) 181 aio_rename $srcpath, $dstpath, $callback->($status)
182 aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
177 aio_mkdir $pathname, $mode, $callback->($status) 183 aio_mkdir $pathname, $mode, $callback->($status)
178 aio_rmdir $pathname, $callback->($status) 184 aio_rmdir $pathname, $callback->($status)
179 aio_readdir $pathname, $callback->($entries) 185 aio_readdir $pathname, $callback->($entries)
180 aio_readdirx $pathname, $flags, $callback->($entries, $flags) 186 aio_readdirx $pathname, $flags, $callback->($entries, $flags)
181 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST 187 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
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183 aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs) 189 aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
184 aio_load $pathname, $data, $callback->($status) 190 aio_load $pathname, $data, $callback->($status)
185 aio_copy $srcpath, $dstpath, $callback->($status) 191 aio_copy $srcpath, $dstpath, $callback->($status)
186 aio_move $srcpath, $dstpath, $callback->($status) 192 aio_move $srcpath, $dstpath, $callback->($status)
187 aio_rmtree $pathname, $callback->($status) 193 aio_rmtree $pathname, $callback->($status)
194 aio_fcntl $fh, $cmd, $arg, $callback->($status)
195 aio_ioctl $fh, $request, $buf, $callback->($status)
188 aio_sync $callback->($status) 196 aio_sync $callback->($status)
189 aio_syncfs $fh, $callback->($status) 197 aio_syncfs $fh, $callback->($status)
190 aio_fsync $fh, $callback->($status) 198 aio_fsync $fh, $callback->($status)
191 aio_fdatasync $fh, $callback->($status) 199 aio_fdatasync $fh, $callback->($status)
192 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status) 200 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
193 aio_pathsync $pathname, $callback->($status) 201 aio_pathsync $pathname, $callback->($status)
194 aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 202 aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
195 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 203 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
196 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) 204 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
197 aio_mlockall $flags, $callback->($status) 205 aio_mlockall $flags, $callback->($status)
198 aio_group $callback->(...) 206 aio_group $callback->(...)
199 aio_nop $callback->() 207 aio_nop $callback->()
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213 IO::AIO::idle_timeout $seconds 221 IO::AIO::idle_timeout $seconds
214 IO::AIO::max_outstanding $maxreqs 222 IO::AIO::max_outstanding $maxreqs
215 IO::AIO::nreqs 223 IO::AIO::nreqs
216 IO::AIO::nready 224 IO::AIO::nready
217 IO::AIO::npending 225 IO::AIO::npending
226 IO::AIO::reinit
227
228 $nfd = IO::AIO::get_fdlimit
229 IO::AIO::min_fdlimit $nfd
218 230
219 IO::AIO::sendfile $ofh, $ifh, $offset, $count 231 IO::AIO::sendfile $ofh, $ifh, $offset, $count
220 IO::AIO::fadvise $fh, $offset, $len, $advice 232 IO::AIO::fadvise $fh, $offset, $len, $advice
233
234 IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
235 IO::AIO::munmap $scalar
236 IO::AIO::mremap $scalar, $new_length, $flags[, $new_address]
221 IO::AIO::madvise $scalar, $offset, $length, $advice 237 IO::AIO::madvise $scalar, $offset, $length, $advice
222 IO::AIO::mprotect $scalar, $offset, $length, $protect 238 IO::AIO::mprotect $scalar, $offset, $length, $protect
223 IO::AIO::munlock $scalar, $offset = 0, $length = undef 239 IO::AIO::munlock $scalar, $offset = 0, $length = undef
224 IO::AIO::munlockall 240 IO::AIO::munlockall
241
242 # stat extensions
243 $counter = IO::AIO::st_gen
244 $seconds = IO::AIO::st_atime, IO::AIO::st_mtime, IO::AIO::st_ctime, IO::AIO::st_btime
245 ($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtime
246 $nanoseconds = IO::AIO::st_atimensec, IO::AIO::st_mtimensec, IO::AIO::st_ctimensec, IO::AIO::st_btimensec
247 $seconds = IO::AIO::st_btimesec
248 ($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtimensec
249
250 # very much unportable syscalls
251 IO::AIO::accept4 $r_fh, $sockaddr, $sockaddr_len, $flags
252 IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
253 IO::AIO::tee $r_fh, $w_fh, $length, $flags
254 $actual_size = IO::AIO::pipesize $r_fh[, $new_size]
255 ($rfh, $wfh) = IO::AIO::pipe2 [$flags]
256 $fh = IO::AIO::memfd_create $pathname[, $flags]
257 $fh = IO::AIO::eventfd [$initval, [$flags]]
258 $fh = IO::AIO::timerfd_create $clockid[, $flags]
259 ($cur_interval, $cur_value) = IO::AIO::timerfd_settime $fh, $flags, $new_interval, $nbw_value
260 ($cur_interval, $cur_value) = IO::AIO::timerfd_gettime $fh
225 261
226 API NOTES 262 API NOTES
227 All the "aio_*" calls are more or less thin wrappers around the syscall 263 All the "aio_*" calls are more or less thin wrappers around the syscall
228 with the same name (sans "aio_"). The arguments are similar or 264 with the same name (sans "aio_"). The arguments are similar or
229 identical, and they all accept an additional (and optional) $callback 265 identical, and they all accept an additional (and optional) $callback
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293 Similar to "aioreq_pri", but subtracts the given value from the 329 Similar to "aioreq_pri", but subtracts the given value from the
294 current priority, so the effect is cumulative. 330 current priority, so the effect is cumulative.
295 331
296 aio_open $pathname, $flags, $mode, $callback->($fh) 332 aio_open $pathname, $flags, $mode, $callback->($fh)
297 Asynchronously open or create a file and call the callback with a 333 Asynchronously open or create a file and call the callback with a
298 newly created filehandle for the file. 334 newly created filehandle for the file (or "undef" in case of an
335 error).
299 336
300 The pathname passed to "aio_open" must be absolute. See API NOTES, 337 The pathname passed to "aio_open" must be absolute. See API NOTES,
301 above, for an explanation. 338 above, for an explanation.
302 339
303 The $flags argument is a bitmask. See the "Fcntl" module for a list. 340 The $flags argument is a bitmask. See the "Fcntl" module for a list.
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326 "O_APPEND"), the following POSIX and non-POSIX constants are 363 "O_APPEND"), the following POSIX and non-POSIX constants are
327 available (missing ones on your system are, as usual, 0): 364 available (missing ones on your system are, as usual, 0):
328 365
329 "O_ASYNC", "O_DIRECT", "O_NOATIME", "O_CLOEXEC", "O_NOCTTY", 366 "O_ASYNC", "O_DIRECT", "O_NOATIME", "O_CLOEXEC", "O_NOCTTY",
330 "O_NOFOLLOW", "O_NONBLOCK", "O_EXEC", "O_SEARCH", "O_DIRECTORY", 367 "O_NOFOLLOW", "O_NONBLOCK", "O_EXEC", "O_SEARCH", "O_DIRECTORY",
331 "O_DSYNC", "O_RSYNC", "O_SYNC" and "O_TTY_INIT". 368 "O_DSYNC", "O_RSYNC", "O_SYNC", "O_PATH", "O_TMPFILE", "O_TTY_INIT"
369 and "O_ACCMODE".
332 370
333 aio_close $fh, $callback->($status) 371 aio_close $fh, $callback->($status)
334 Asynchronously close a file and call the callback with the result 372 Asynchronously close a file and call the callback with the result
335 code. 373 code.
336 374
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356 394
357 In theory, the $whence constants could be different than the 395 In theory, the $whence constants could be different than the
358 corresponding values from Fcntl, but perl guarantees they are the 396 corresponding values from Fcntl, but perl guarantees they are the
359 same, so don't panic. 397 same, so don't panic.
360 398
399 As a GNU/Linux (and maybe Solaris) extension, also the constants
400 "IO::AIO::SEEK_DATA" and "IO::AIO::SEEK_HOLE" are available, if they
401 could be found. No guarantees about suitability for use in
402 "aio_seek" or Perl's "sysseek" can be made though, although I would
403 naively assume they "just work".
404
361 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 405 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
362 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 406 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
363 Reads or writes $length bytes from or to the specified $fh and 407 Reads or writes $length bytes from or to the specified $fh and
364 $offset into the scalar given by $data and offset $dataoffset and 408 $offset into the scalar given by $data and offset $dataoffset and
365 calls the callback without the actual number of bytes read (or -1 on 409 calls the callback with the actual number of bytes transferred (or
366 error, just like the syscall). 410 -1 on error, just like the syscall).
367 411
368 "aio_read" will, like "sysread", shrink or grow the $data scalar to 412 "aio_read" will, like "sysread", shrink or grow the $data scalar to
369 offset plus the actual number of bytes read. 413 offset plus the actual number of bytes read.
370 414
371 If $offset is undefined, then the current file descriptor offset 415 If $offset is undefined, then the current file descriptor offset
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428 As native sendfile syscalls (as practically any non-POSIX interface 472 As native sendfile syscalls (as practically any non-POSIX interface
429 hacked together in a hurry to improve benchmark numbers) tend to be 473 hacked together in a hurry to improve benchmark numbers) tend to be
430 rather buggy on many systems, this implementation tries to work 474 rather buggy on many systems, this implementation tries to work
431 around some known bugs in Linux and FreeBSD kernels (probably 475 around some known bugs in Linux and FreeBSD kernels (probably
432 others, too), but that might fail, so you really really should check 476 others, too), but that might fail, so you really really should check
433 the return value of "aio_sendfile" - fewre bytes than expected might 477 the return value of "aio_sendfile" - fewer bytes than expected might
434 have been transferred. 478 have been transferred.
435 479
436 aio_readahead $fh,$offset,$length, $callback->($retval) 480 aio_readahead $fh,$offset,$length, $callback->($retval)
437 "aio_readahead" populates the page cache with data from a file so 481 "aio_readahead" populates the page cache with data from a file so
438 that subsequent reads from that file will not block on disk I/O. The 482 that subsequent reads from that file will not block on disk I/O. The
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442 to a page boundary and bytes are read up to the next page boundary 486 to a page boundary and bytes are read up to the next page boundary
443 greater than or equal to (off-set+length). "aio_readahead" does not 487 greater than or equal to (off-set+length). "aio_readahead" does not
444 read beyond the end of the file. The current file offset of the file 488 read beyond the end of the file. The current file offset of the file
445 is left unchanged. 489 is left unchanged.
446 490
447 If that syscall doesn't exist (likely if your OS isn't Linux) it 491 If that syscall doesn't exist (likely if your kernel isn't Linux) it
448 will be emulated by simply reading the data, which would have a 492 will be emulated by simply reading the data, which would have a
449 similar effect. 493 similar effect.
450 494
451 aio_stat $fh_or_path, $callback->($status) 495 aio_stat $fh_or_path, $callback->($status)
452 aio_lstat $fh, $callback->($status) 496 aio_lstat $fh, $callback->($status)
453 Works like perl's "stat" or "lstat" in void context. The callback 497 Works almost exactly like perl's "stat" or "lstat" in void context.
454 will be called after the stat and the results will be available 498 The callback will be called after the stat and the results will be
455 using "stat _" or "-s _" etc... 499 available using "stat _" or "-s _" and other tests (with the
500 exception of "-B" and "-T").
456 501
457 The pathname passed to "aio_stat" must be absolute. See API NOTES, 502 The pathname passed to "aio_stat" must be absolute. See API NOTES,
458 above, for an explanation. 503 above, for an explanation.
459 504
460 Currently, the stats are always 64-bit-stats, i.e. instead of 505 Currently, the stats are always 64-bit-stats, i.e. instead of
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468 back on traditional behaviour). 513 back on traditional behaviour).
469 514
470 "S_IFMT", "S_IFIFO", "S_IFCHR", "S_IFBLK", "S_IFLNK", "S_IFREG", 515 "S_IFMT", "S_IFIFO", "S_IFCHR", "S_IFBLK", "S_IFLNK", "S_IFREG",
471 "S_IFDIR", "S_IFWHT", "S_IFSOCK", "IO::AIO::major $dev_t", 516 "S_IFDIR", "S_IFWHT", "S_IFSOCK", "IO::AIO::major $dev_t",
472 "IO::AIO::minor $dev_t", "IO::AIO::makedev $major, $minor". 517 "IO::AIO::minor $dev_t", "IO::AIO::makedev $major, $minor".
518
519 To access higher resolution stat timestamps, see "SUBSECOND STAT
520 TIME ACCESS".
473 521
474 Example: Print the length of /etc/passwd: 522 Example: Print the length of /etc/passwd:
475 523
476 aio_stat "/etc/passwd", sub { 524 aio_stat "/etc/passwd", sub {
477 $_[0] and die "stat failed: $!"; 525 $_[0] and die "stat failed: $!";
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524 aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 572 aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
525 Works like perl's "utime" function (including the special case of 573 Works like perl's "utime" function (including the special case of
526 $atime and $mtime being undef). Fractional times are supported if 574 $atime and $mtime being undef). Fractional times are supported if
527 the underlying syscalls support them. 575 the underlying syscalls support them.
528 576
529 When called with a pathname, uses utimes(2) if available, otherwise 577 When called with a pathname, uses utimensat(2) or utimes(2) if
530 utime(2). If called on a file descriptor, uses futimes(2) if 578 available, otherwise utime(2). If called on a file descriptor, uses
531 available, otherwise returns ENOSYS, so this is not portable. 579 futimens(2) or futimes(2) if available, otherwise returns ENOSYS, so
580 this is not portable.
532 581
533 Examples: 582 Examples:
534 583
535 # set atime and mtime to current time (basically touch(1)): 584 # set atime and mtime to current time (basically touch(1)):
536 aio_utime "path", undef, undef; 585 aio_utime "path", undef, undef;
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550 aio_chown "path", 0, undef; 599 aio_chown "path", 0, undef;
551 600
552 aio_truncate $fh_or_path, $offset, $callback->($status) 601 aio_truncate $fh_or_path, $offset, $callback->($status)
553 Works like truncate(2) or ftruncate(2). 602 Works like truncate(2) or ftruncate(2).
554 603
604 aio_allocate $fh, $mode, $offset, $len, $callback->($status)
605 Allocates or frees disk space according to the $mode argument. See
606 the linux "fallocate" documentation for details.
607
608 $mode is usually 0 or "IO::AIO::FALLOC_FL_KEEP_SIZE" to allocate
609 space, or "IO::AIO::FALLOC_FL_PUNCH_HOLE |
610 IO::AIO::FALLOC_FL_KEEP_SIZE", to deallocate a file range.
611
612 IO::AIO also supports "FALLOC_FL_COLLAPSE_RANGE", to remove a range
613 (without leaving a hole), "FALLOC_FL_ZERO_RANGE", to zero a range,
614 "FALLOC_FL_INSERT_RANGE" to insert a range and
615 "FALLOC_FL_UNSHARE_RANGE" to unshare shared blocks (see your
616 fallocate(2) manpage).
617
618 The file system block size used by "fallocate" is presumably the
619 "f_bsize" returned by "statvfs", but different filesystems and
620 filetypes can dictate other limitations.
621
622 If "fallocate" isn't available or cannot be emulated (currently no
623 emulation will be attempted), passes -1 and sets $! to "ENOSYS".
624
555 aio_chmod $fh_or_path, $mode, $callback->($status) 625 aio_chmod $fh_or_path, $mode, $callback->($status)
556 Works like perl's "chmod" function. 626 Works like perl's "chmod" function.
557 627
558 aio_unlink $pathname, $callback->($status) 628 aio_unlink $pathname, $callback->($status)
559 Asynchronously unlink (delete) a file and call the callback with the 629 Asynchronously unlink (delete) a file and call the callback with the
… …
585 the callback. If an error occurs, nothing or undef gets passed to 655 the callback. If an error occurs, nothing or undef gets passed to
586 the callback. 656 the callback.
587 657
588 aio_realpath $pathname, $callback->($path) 658 aio_realpath $pathname, $callback->($path)
589 Asynchronously make the path absolute and resolve any symlinks in 659 Asynchronously make the path absolute and resolve any symlinks in
590 $path. The resulting path only consists of directories (Same as 660 $path. The resulting path only consists of directories (same as
591 Cwd::realpath). 661 Cwd::realpath).
592 662
593 This request can be used to get the absolute path of the current 663 This request can be used to get the absolute path of the current
594 working directory by passing it a path of . (a single dot). 664 working directory by passing it a path of . (a single dot).
595 665
596 aio_rename $srcpath, $dstpath, $callback->($status) 666 aio_rename $srcpath, $dstpath, $callback->($status)
597 Asynchronously rename the object at $srcpath to $dstpath, just as 667 Asynchronously rename the object at $srcpath to $dstpath, just as
598 rename(2) and call the callback with the result code. 668 rename(2) and call the callback with the result code.
669
670 On systems that support the AIO::WD working directory abstraction
671 natively, the case "[$wd, "."]" as $srcpath is specialcased -
672 instead of failing, "rename" is called on the absolute path of $wd.
673
674 aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
675 Basically a version of "aio_rename" with an additional $flags
676 argument. Calling this with "$flags=0" is the same as calling
677 "aio_rename".
678
679 Non-zero flags are currently only supported on GNU/Linux systems
680 that support renameat2. Other systems fail with "ENOSYS" in this
681 case.
682
683 The following constants are available (missing ones are, as usual
684 0), see renameat2(2) for details:
685
686 "IO::AIO::RENAME_NOREPLACE", "IO::AIO::RENAME_EXCHANGE" and
687 "IO::AIO::RENAME_WHITEOUT".
599 688
600 aio_mkdir $pathname, $mode, $callback->($status) 689 aio_mkdir $pathname, $mode, $callback->($status)
601 Asynchronously mkdir (create) a directory and call the callback with 690 Asynchronously mkdir (create) a directory and call the callback with
602 the result code. $mode will be modified by the umask at the time the 691 the result code. $mode will be modified by the umask at the time the
603 request is executed, so do not change your umask. 692 request is executed, so do not change your umask.
604 693
605 aio_rmdir $pathname, $callback->($status) 694 aio_rmdir $pathname, $callback->($status)
606 Asynchronously rmdir (delete) a directory and call the callback with 695 Asynchronously rmdir (delete) a directory and call the callback with
607 the result code. 696 the result code.
608 697
698 On systems that support the AIO::WD working directory abstraction
699 natively, the case "[$wd, "."]" is specialcased - instead of
700 failing, "rmdir" is called on the absolute path of $wd.
701
609 aio_readdir $pathname, $callback->($entries) 702 aio_readdir $pathname, $callback->($entries)
610 Unlike the POSIX call of the same name, "aio_readdir" reads an 703 Unlike the POSIX call of the same name, "aio_readdir" reads an
611 entire directory (i.e. opendir + readdir + closedir). The entries 704 entire directory (i.e. opendir + readdir + closedir). The entries
612 will not be sorted, and will NOT include the "." and ".." entries. 705 will not be sorted, and will NOT include the "." and ".." entries.
613 706
… …
622 The flags are a combination of the following constants, ORed 715 The flags are a combination of the following constants, ORed
623 together (the flags will also be passed to the callback, possibly 716 together (the flags will also be passed to the callback, possibly
624 modified): 717 modified):
625 718
626 IO::AIO::READDIR_DENTS 719 IO::AIO::READDIR_DENTS
627 When this flag is off, then the callback gets an arrayref 720 Normally the callback gets an arrayref consisting of names only
628 consisting of names only (as with "aio_readdir"), otherwise it 721 (as with "aio_readdir"). If this flag is set, then the callback
629 gets an arrayref with "[$name, $type, $inode]" arrayrefs, each 722 gets an arrayref with "[$name, $type, $inode]" arrayrefs, each
630 describing a single directory entry in more detail. 723 describing a single directory entry in more detail:
631 724
632 $name is the name of the entry. 725 $name is the name of the entry.
633 726
634 $type is one of the "IO::AIO::DT_xxx" constants: 727 $type is one of the "IO::AIO::DT_xxx" constants:
635 728
636 "IO::AIO::DT_UNKNOWN", "IO::AIO::DT_FIFO", "IO::AIO::DT_CHR", 729 "IO::AIO::DT_UNKNOWN", "IO::AIO::DT_FIFO", "IO::AIO::DT_CHR",
637 "IO::AIO::DT_DIR", "IO::AIO::DT_BLK", "IO::AIO::DT_REG", 730 "IO::AIO::DT_DIR", "IO::AIO::DT_BLK", "IO::AIO::DT_REG",
638 "IO::AIO::DT_LNK", "IO::AIO::DT_SOCK", "IO::AIO::DT_WHT". 731 "IO::AIO::DT_LNK", "IO::AIO::DT_SOCK", "IO::AIO::DT_WHT".
639 732
640 "IO::AIO::DT_UNKNOWN" means just that: readdir does not know. If 733 "IO::AIO::DT_UNKNOWN" means just that: readdir does not know. If
641 you need to know, you have to run stat yourself. Also, for speed 734 you need to know, you have to run stat yourself. Also, for
642 reasons, the $type scalars are read-only: you can not modify 735 speed/memory reasons, the $type scalars are read-only: you must
643 them. 736 not modify them.
644 737
645 $inode is the inode number (which might not be exact on systems 738 $inode is the inode number (which might not be exact on systems
646 with 64 bit inode numbers and 32 bit perls). This field has 739 with 64 bit inode numbers and 32 bit perls). This field has
647 unspecified content on systems that do not deliver the inode 740 unspecified content on systems that do not deliver the inode
648 information. 741 information.
… …
660 of which names with short names are tried first. 753 of which names with short names are tried first.
661 754
662 IO::AIO::READDIR_STAT_ORDER 755 IO::AIO::READDIR_STAT_ORDER
663 When this flag is set, then the names will be returned in an 756 When this flag is set, then the names will be returned in an
664 order suitable for stat()'ing each one. That is, when you plan 757 order suitable for stat()'ing each one. That is, when you plan
665 to stat() all files in the given directory, then the returned 758 to stat() most or all files in the given directory, then the
666 order will likely be fastest. 759 returned order will likely be faster.
667 760
668 If both this flag and "IO::AIO::READDIR_DIRS_FIRST" are 761 If both this flag and "IO::AIO::READDIR_DIRS_FIRST" are
669 specified, then the likely dirs come first, resulting in a less 762 specified, then the likely dirs come first, resulting in a less
670 optimal stat order. 763 optimal stat order for stat'ing all entries, but likely a more
764 optimal order for finding subdirectories.
671 765
672 IO::AIO::READDIR_FOUND_UNKNOWN 766 IO::AIO::READDIR_FOUND_UNKNOWN
673 This flag should not be set when calling "aio_readdirx". 767 This flag should not be set when calling "aio_readdirx".
674 Instead, it is being set by "aio_readdirx", when any of the 768 Instead, it is being set by "aio_readdirx", when any of the
675 $type's found were "IO::AIO::DT_UNKNOWN". The absence of this 769 $type's found were "IO::AIO::DT_UNKNOWN". The absence of this
676 flag therefore indicates that all $type's are known, which can 770 flag therefore indicates that all $type's are known, which can
677 be used to speed up some algorithms. 771 be used to speed up some algorithms.
678 772
773 aio_slurp $pathname, $offset, $length, $data, $callback->($status)
774 Opens, reads and closes the given file. The data is put into $data,
775 which is resized as required.
776
777 If $offset is negative, then it is counted from the end of the file.
778
779 If $length is zero, then the remaining length of the file is used.
780 Also, in this case, the same limitations to modifying $data apply as
781 when IO::AIO::mmap is used, i.e. it must only be modified in-place
782 with "substr". If the size of the file is known, specifying a
783 non-zero $length results in a performance advantage.
784
785 This request is similar to the older "aio_load" request, but since
786 it is a single request, it might be more efficient to use.
787
788 Example: load /etc/passwd into $passwd.
789
790 my $passwd;
791 aio_slurp "/etc/passwd", 0, 0, $passwd, sub {
792 $_[0] >= 0
793 or die "/etc/passwd: $!\n";
794
795 printf "/etc/passwd is %d bytes long, and contains:\n", length $passwd;
796 print $passwd;
797 };
798 IO::AIO::flush;
799
679 aio_load $pathname, $data, $callback->($status) 800 aio_load $pathname, $data, $callback->($status)
680 This is a composite request that tries to fully load the given file 801 This is a composite request that tries to fully load the given file
681 into memory. Status is the same as with aio_read. 802 into memory. Status is the same as with aio_read.
803
804 Using "aio_slurp" might be more efficient, as it is a single
805 request.
682 806
683 aio_copy $srcpath, $dstpath, $callback->($status) 807 aio_copy $srcpath, $dstpath, $callback->($status)
684 Try to copy the *file* (directories not supported as either source 808 Try to copy the *file* (directories not supported as either source
685 or destination) from $srcpath to $dstpath and call the callback with 809 or destination) from $srcpath to $dstpath and call the callback with
686 a status of 0 (ok) or -1 (error, see $!). 810 a status of 0 (ok) or -1 (error, see $!).
811
812 Existing destination files will be truncated.
687 813
688 This is a composite request that creates the destination file with 814 This is a composite request that creates the destination file with
689 mode 0200 and copies the contents of the source file into it using 815 mode 0200 and copies the contents of the source file into it using
690 "aio_sendfile", followed by restoring atime, mtime, access mode and 816 "aio_sendfile", followed by restoring atime, mtime, access mode and
691 uid/gid, in that order. 817 uid/gid, in that order.
… …
708 to efficiently separate the entries of directory $path into two sets 834 to efficiently separate the entries of directory $path into two sets
709 of names, directories you can recurse into (directories), and ones 835 of names, directories you can recurse into (directories), and ones
710 you cannot recurse into (everything else, including symlinks to 836 you cannot recurse into (everything else, including symlinks to
711 directories). 837 directories).
712 838
713 "aio_scandir" is a composite request that creates of many sub 839 "aio_scandir" is a composite request that generates many sub
714 requests_ $maxreq specifies the maximum number of outstanding aio 840 requests. $maxreq specifies the maximum number of outstanding aio
715 requests that this function generates. If it is "<= 0", then a 841 requests that this function generates. If it is "<= 0", then a
716 suitable default will be chosen (currently 4). 842 suitable default will be chosen (currently 4).
717 843
718 On error, the callback is called without arguments, otherwise it 844 On error, the callback is called without arguments, otherwise it
719 receives two array-refs with path-relative entry names. 845 receives two array-refs with path-relative entry names.
… …
766 Delete a directory tree starting (and including) $path, return the 892 Delete a directory tree starting (and including) $path, return the
767 status of the final "rmdir" only. This is a composite request that 893 status of the final "rmdir" only. This is a composite request that
768 uses "aio_scandir" to recurse into and rmdir directories, and unlink 894 uses "aio_scandir" to recurse into and rmdir directories, and unlink
769 everything else. 895 everything else.
770 896
897 aio_fcntl $fh, $cmd, $arg, $callback->($status)
898 aio_ioctl $fh, $request, $buf, $callback->($status)
899 These work just like the "fcntl" and "ioctl" built-in functions,
900 except they execute asynchronously and pass the return value to the
901 callback.
902
903 Both calls can be used for a lot of things, some of which make more
904 sense to run asynchronously in their own thread, while some others
905 make less sense. For example, calls that block waiting for external
906 events, such as locking, will also lock down an I/O thread while it
907 is waiting, which can deadlock the whole I/O system. At the same
908 time, there might be no alternative to using a thread to wait.
909
910 So in general, you should only use these calls for things that do
911 (filesystem) I/O, not for things that wait for other events
912 (network, other processes), although if you are careful and know
913 what you are doing, you still can.
914
915 The following constants are available and can be used for normal
916 "ioctl" and "fcntl" as well (missing ones are, as usual 0):
917
918 "F_DUPFD_CLOEXEC",
919
920 "F_OFD_GETLK", "F_OFD_SETLK", "F_OFD_GETLKW",
921
922 "FIFREEZE", "FITHAW", "FITRIM", "FICLONE", "FICLONERANGE",
923 "FIDEDUPERANGE".
924
925 "F_ADD_SEALS", "F_GET_SEALS", "F_SEAL_SEAL", "F_SEAL_SHRINK",
926 "F_SEAL_GROW" and "F_SEAL_WRITE".
927
928 "FS_IOC_GETFLAGS", "FS_IOC_SETFLAGS", "FS_IOC_GETVERSION",
929 "FS_IOC_SETVERSION", "FS_IOC_FIEMAP".
930
931 "FS_IOC_FSGETXATTR", "FS_IOC_FSSETXATTR",
932 "FS_IOC_SET_ENCRYPTION_POLICY", "FS_IOC_GET_ENCRYPTION_PWSALT",
933 "FS_IOC_GET_ENCRYPTION_POLICY", "FS_KEY_DESCRIPTOR_SIZE".
934
935 "FS_SECRM_FL", "FS_UNRM_FL", "FS_COMPR_FL", "FS_SYNC_FL",
936 "FS_IMMUTABLE_FL", "FS_APPEND_FL", "FS_NODUMP_FL", "FS_NOATIME_FL",
937 "FS_DIRTY_FL", "FS_COMPRBLK_FL", "FS_NOCOMP_FL", "FS_ENCRYPT_FL",
938 "FS_BTREE_FL", "FS_INDEX_FL", "FS_JOURNAL_DATA_FL", "FS_NOTAIL_FL",
939 "FS_DIRSYNC_FL", "FS_TOPDIR_FL", "FS_FL_USER_MODIFIABLE".
940
941 "FS_XFLAG_REALTIME", "FS_XFLAG_PREALLOC", "FS_XFLAG_IMMUTABLE",
942 "FS_XFLAG_APPEND", "FS_XFLAG_SYNC", "FS_XFLAG_NOATIME",
943 "FS_XFLAG_NODUMP", "FS_XFLAG_RTINHERIT", "FS_XFLAG_PROJINHERIT",
944 "FS_XFLAG_NOSYMLINKS", "FS_XFLAG_EXTSIZE", "FS_XFLAG_EXTSZINHERIT",
945 "FS_XFLAG_NODEFRAG", "FS_XFLAG_FILESTREAM", "FS_XFLAG_DAX",
946 "FS_XFLAG_HASATTR",
947
771 aio_sync $callback->($status) 948 aio_sync $callback->($status)
772 Asynchronously call sync and call the callback when finished. 949 Asynchronously call sync and call the callback when finished.
773 950
774 aio_fsync $fh, $callback->($status) 951 aio_fsync $fh, $callback->($status)
775 Asynchronously call fsync on the given filehandle and call the 952 Asynchronously call fsync on the given filehandle and call the
… …
811 Future versions of this function might fall back to other methods 988 Future versions of this function might fall back to other methods
812 when "fsync" on the directory fails (such as calling "sync"). 989 when "fsync" on the directory fails (such as calling "sync").
813 990
814 Passes 0 when everything went ok, and -1 on error. 991 Passes 0 when everything went ok, and -1 on error.
815 992
816 aio_msync $scalar, $offset = 0, $length = undef, flags = 0, 993 aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC,
817 $callback->($status) 994 $callback->($status)
818 This is a rather advanced IO::AIO call, which only works on 995 This is a rather advanced IO::AIO call, which only works on
819 mmap(2)ed scalars (see the "IO::AIO::mmap" function, although it 996 mmap(2)ed scalars (see the "IO::AIO::mmap" function, although it
820 also works on data scalars managed by the Sys::Mmap or Mmap modules, 997 also works on data scalars managed by the Sys::Mmap or Mmap modules,
821 note that the scalar must only be modified in-place while an aio 998 note that the scalar must only be modified in-place while an aio
… …
823 1000
824 It calls the "msync" function of your OS, if available, with the 1001 It calls the "msync" function of your OS, if available, with the
825 memory area starting at $offset in the string and ending $length 1002 memory area starting at $offset in the string and ending $length
826 bytes later. If $length is negative, counts from the end, and if 1003 bytes later. If $length is negative, counts from the end, and if
827 $length is "undef", then it goes till the end of the string. The 1004 $length is "undef", then it goes till the end of the string. The
828 flags can be a combination of "IO::AIO::MS_ASYNC", 1005 flags can be either "IO::AIO::MS_ASYNC" or "IO::AIO::MS_SYNC", plus
829 "IO::AIO::MS_INVALIDATE" and "IO::AIO::MS_SYNC". 1006 an optional "IO::AIO::MS_INVALIDATE".
830 1007
831 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, 1008 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0,
832 $callback->($status) 1009 $callback->($status)
833 This is a rather advanced IO::AIO call, which works best on 1010 This is a rather advanced IO::AIO call, which works best on
834 mmap(2)ed scalars. 1011 mmap(2)ed scalars.
835 1012
836 It touches (reads or writes) all memory pages in the specified range 1013 It touches (reads or writes) all memory pages in the specified range
837 inside the scalar. All caveats and parameters are the same as for 1014 inside the scalar. All caveats and parameters are the same as for
838 "aio_msync", above, except for flags, which must be either 0 (which 1015 "aio_msync", above, except for flags, which must be either 0 (which
839 reads all pages and ensures they are instantiated) or 1016 reads all pages and ensures they are instantiated) or
840 "IO::AIO::MT_MODIFY", which modifies the memory page s(by reading 1017 "IO::AIO::MT_MODIFY", which modifies the memory pages (by reading
841 and writing an octet from it, which dirties the page). 1018 and writing an octet from it, which dirties the page).
842 1019
843 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) 1020 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
844 This is a rather advanced IO::AIO call, which works best on 1021 This is a rather advanced IO::AIO call, which works best on
845 mmap(2)ed scalars. 1022 mmap(2)ed scalars.
… …
865 IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh; 1042 IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
866 aio_mlock $data; # mlock in background 1043 aio_mlock $data; # mlock in background
867 1044
868 aio_mlockall $flags, $callback->($status) 1045 aio_mlockall $flags, $callback->($status)
869 Calls the "mlockall" function with the given $flags (a combination 1046 Calls the "mlockall" function with the given $flags (a combination
870 of "IO::AIO::MCL_CURRENT" and "IO::AIO::MCL_FUTURE"). 1047 of "IO::AIO::MCL_CURRENT", "IO::AIO::MCL_FUTURE" and
1048 "IO::AIO::MCL_ONFAULT").
871 1049
872 On systems that do not implement "mlockall", this function returns 1050 On systems that do not implement "mlockall", this function returns
873 -1 and sets errno to "ENOSYS". 1051 -1 and sets errno to "ENOSYS". Similarly, flag combinations not
1052 supported by the system result in a return value of -1 with errno
1053 being set to "EINVAL".
874 1054
875 Note that the corresponding "munlockall" is synchronous and is 1055 Note that the corresponding "munlockall" is synchronous and is
876 documented under "MISCELLANEOUS FUNCTIONS". 1056 documented under "MISCELLANEOUS FUNCTIONS".
877 1057
878 Example: asynchronously lock all current and future pages into 1058 Example: asynchronously lock all current and future pages into
879 memory. 1059 memory.
880 1060
881 aio_mlockall IO::AIO::MCL_FUTURE; 1061 aio_mlockall IO::AIO::MCL_FUTURE;
882 1062
883 aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents) 1063 aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
884 Queries the extents of the given file (by calling the Linux FIEMAP 1064 Queries the extents of the given file (by calling the Linux "FIEMAP"
885 ioctl, see <http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for 1065 ioctl, see <http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for
886 details). If the "ioctl" is not available on your OS, then this 1066 details). If the ioctl is not available on your OS, then this
887 rquiest will fail with "ENOSYS". 1067 request will fail with "ENOSYS".
888 1068
889 $start is the starting offset to query extents for, $length is the 1069 $start is the starting offset to query extents for, $length is the
890 size of the range to query - if it is "undef", then the whole file 1070 size of the range to query - if it is "undef", then the whole file
891 will be queried. 1071 will be queried.
892 1072
… …
894 "IO::AIO::FIEMAP_FLAG_XATTR" - "IO::AIO::FIEMAP_FLAGS_COMPAT" is 1074 "IO::AIO::FIEMAP_FLAG_XATTR" - "IO::AIO::FIEMAP_FLAGS_COMPAT" is
895 also exported), and is normally 0 or "IO::AIO::FIEMAP_FLAG_SYNC" to 1075 also exported), and is normally 0 or "IO::AIO::FIEMAP_FLAG_SYNC" to
896 query the data portion. 1076 query the data portion.
897 1077
898 $count is the maximum number of extent records to return. If it is 1078 $count is the maximum number of extent records to return. If it is
899 "undef", then IO::AIO queries all extents of the file. As a very 1079 "undef", then IO::AIO queries all extents of the range. As a very
900 special case, if it is 0, then the callback receives the number of 1080 special case, if it is 0, then the callback receives the number of
901 extents instead of the extents themselves. 1081 extents instead of the extents themselves (which is unreliable, see
1082 below).
902 1083
903 If an error occurs, the callback receives no arguments. The special 1084 If an error occurs, the callback receives no arguments. The special
904 "errno" value "IO::AIO::EBADR" is available to test for flag errors. 1085 "errno" value "IO::AIO::EBADR" is available to test for flag errors.
905 1086
906 Otherwise, the callback receives an array reference with extent 1087 Otherwise, the callback receives an array reference with extent
… …
908 the following members: 1089 the following members:
909 1090
910 [$logical, $physical, $length, $flags] 1091 [$logical, $physical, $length, $flags]
911 1092
912 Flags is any combination of the following flag values (typically 1093 Flags is any combination of the following flag values (typically
913 either 0 or "IO::AIO::FIEMAP_EXTENT_LAST"): 1094 either 0 or "IO::AIO::FIEMAP_EXTENT_LAST" (1)):
914 1095
915 "IO::AIO::FIEMAP_EXTENT_LAST", "IO::AIO::FIEMAP_EXTENT_UNKNOWN", 1096 "IO::AIO::FIEMAP_EXTENT_LAST", "IO::AIO::FIEMAP_EXTENT_UNKNOWN",
916 "IO::AIO::FIEMAP_EXTENT_DELALLOC", "IO::AIO::FIEMAP_EXTENT_ENCODED", 1097 "IO::AIO::FIEMAP_EXTENT_DELALLOC", "IO::AIO::FIEMAP_EXTENT_ENCODED",
917 "IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED", 1098 "IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED",
918 "IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED", 1099 "IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED",
919 "IO::AIO::FIEMAP_EXTENT_DATA_INLINE", 1100 "IO::AIO::FIEMAP_EXTENT_DATA_INLINE",
920 "IO::AIO::FIEMAP_EXTENT_DATA_TAIL", 1101 "IO::AIO::FIEMAP_EXTENT_DATA_TAIL",
921 "IO::AIO::FIEMAP_EXTENT_UNWRITTEN", "IO::AIO::FIEMAP_EXTENT_MERGED" 1102 "IO::AIO::FIEMAP_EXTENT_UNWRITTEN", "IO::AIO::FIEMAP_EXTENT_MERGED"
922 or "IO::AIO::FIEMAP_EXTENT_SHARED". 1103 or "IO::AIO::FIEMAP_EXTENT_SHARED".
923 1104
1105 At the time of this writing (Linux 3.2), this request is unreliable
1106 unless $count is "undef", as the kernel has all sorts of bugs
1107 preventing it to return all extents of a range for files with a
1108 large number of extents. The code (only) works around all these
1109 issues if $count is "undef".
1110
924 aio_group $callback->(...) 1111 aio_group $callback->(...)
925 This is a very special aio request: Instead of doing something, it 1112 This is a very special aio request: Instead of doing something, it
926 is a container for other aio requests, which is useful if you want 1113 is a container for other aio requests, which is useful if you want
927 to bundle many requests into a single, composite, request with a 1114 to bundle many requests into a single, composite, request with a
928 definite callback and the ability to cancel the whole request with 1115 definite callback and the ability to cancel the whole request with
… …
1007 aio_stat [$etcdir, "passwd"], sub { 1194 aio_stat [$etcdir, "passwd"], sub {
1008 # yay 1195 # yay
1009 }; 1196 };
1010 }; 1197 };
1011 1198
1012 That "aio_wd" is a request and not a normal function shows that creating 1199 The fact that "aio_wd" is a request and not a normal function shows that
1013 an IO::AIO::WD object is itself a potentially blocking operation, which 1200 creating an IO::AIO::WD object is itself a potentially blocking
1014 is why it is done asynchronously. 1201 operation, which is why it is done asynchronously.
1015 1202
1016 To stat the directory obtained with "aio_wd" above, one could write 1203 To stat the directory obtained with "aio_wd" above, one could write
1017 either of the following three request calls: 1204 either of the following three request calls:
1018 1205
1019 aio_lstat "/etc" , sub { ... # pathname as normal string 1206 aio_lstat "/etc" , sub { ... # pathname as normal string
… …
1036 There are some caveats: when directories get renamed (or deleted), the 1223 There are some caveats: when directories get renamed (or deleted), the
1037 pathname string doesn't change, so will point to the new directory (or 1224 pathname string doesn't change, so will point to the new directory (or
1038 nowhere at all), while the directory fd, if available on the system, 1225 nowhere at all), while the directory fd, if available on the system,
1039 will still point to the original directory. Most functions accepting a 1226 will still point to the original directory. Most functions accepting a
1040 pathname will use the directory fd on newer systems, and the string on 1227 pathname will use the directory fd on newer systems, and the string on
1041 older systems. Some functions (such as realpath) will always rely on the 1228 older systems. Some functions (such as "aio_realpath") will always rely
1042 string form of the pathname. 1229 on the string form of the pathname.
1043 1230
1044 So this fucntionality is mainly useful to get some protection against 1231 So this functionality is mainly useful to get some protection against
1045 "chdir", to easily get an absolute path out of a relative path for 1232 "chdir", to easily get an absolute path out of a relative path for
1046 future reference, and to speed up doing many operations in the same 1233 future reference, and to speed up doing many operations in the same
1047 directory (e.g. when stat'ing all files in a directory). 1234 directory (e.g. when stat'ing all files in a directory).
1048 1235
1049 The following functions implement this working directory abstraction: 1236 The following functions implement this working directory abstraction:
… …
1059 Since passing "undef" as working directory component of a pathname 1246 Since passing "undef" as working directory component of a pathname
1060 fails the request with "ENOENT", there is often no need for error 1247 fails the request with "ENOENT", there is often no need for error
1061 checking in the "aio_wd" callback, as future requests using the 1248 checking in the "aio_wd" callback, as future requests using the
1062 value will fail in the expected way. 1249 value will fail in the expected way.
1063 1250
1064 If this call isn't available because your OS lacks it or it couldn't
1065 be detected, it will be emulated by calling "fsync" instead.
1066
1067 IO::AIO::CWD 1251 IO::AIO::CWD
1068 This is a compiletime constant (object) that represents the process 1252 This is a compile time constant (object) that represents the process
1069 current working directory. 1253 current working directory.
1070 1254
1071 Specifying this object as working directory object for a pathname is 1255 Specifying this object as working directory object for a pathname is
1072 as if the pathname would be specified directly, without a directory 1256 as if the pathname would be specified directly, without a directory
1073 object, e.g., these calls are functionally identical: 1257 object. For example, these calls are functionally identical:
1074 1258
1075 aio_stat "somefile", sub { ... }; 1259 aio_stat "somefile", sub { ... };
1076 aio_stat [IO::AIO::CWD, "somefile"], sub { ... }; 1260 aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
1261
1262 To recover the path associated with an IO::AIO::WD object, you can use
1263 "aio_realpath":
1264
1265 aio_realpath $wd, sub {
1266 warn "path is $_[0]\n";
1267 };
1268
1269 Currently, "aio_statvfs" always, and "aio_rename" and "aio_rmdir"
1270 sometimes, fall back to using an absolue path.
1077 1271
1078 IO::AIO::REQ CLASS 1272 IO::AIO::REQ CLASS
1079 All non-aggregate "aio_*" functions return an object of this class when 1273 All non-aggregate "aio_*" functions return an object of this class when
1080 called in non-void context. 1274 called in non-void context.
1081 1275
… …
1233 results. 1427 results.
1234 1428
1235 See "poll_cb" for an example. 1429 See "poll_cb" for an example.
1236 1430
1237 IO::AIO::poll_cb 1431 IO::AIO::poll_cb
1238 Process some outstanding events on the result pipe. You have to call 1432 Process some requests that have reached the result phase (i.e. they
1433 have been executed but the results are not yet reported). You have
1434 to call this "regularly" to finish outstanding requests.
1435
1239 this regularly. Returns 0 if all events could be processed (or there 1436 Returns 0 if all events could be processed (or there were no events
1240 were no events to process), or -1 if it returned earlier for 1437 to process), or -1 if it returned earlier for whatever reason.
1241 whatever reason. Returns immediately when no events are outstanding. 1438 Returns immediately when no events are outstanding. The amount of
1242 The amount of events processed depends on the settings of 1439 events processed depends on the settings of "IO::AIO::max_poll_req",
1243 "IO::AIO::max_poll_req" and "IO::AIO::max_poll_time". 1440 "IO::AIO::max_poll_time" and "IO::AIO::max_outstanding".
1244 1441
1245 If not all requests were processed for whatever reason, the 1442 If not all requests were processed for whatever reason, the poll
1246 filehandle will still be ready when "poll_cb" returns, so normally 1443 file descriptor will still be ready when "poll_cb" returns, so
1247 you don't have to do anything special to have it called later. 1444 normally you don't have to do anything special to have it called
1445 later.
1248 1446
1249 Apart from calling "IO::AIO::poll_cb" when the event filehandle 1447 Apart from calling "IO::AIO::poll_cb" when the event filehandle
1250 becomes ready, it can be beneficial to call this function from loops 1448 becomes ready, it can be beneficial to call this function from loops
1251 which submit a lot of requests, to make sure the results get 1449 which submit a lot of requests, to make sure the results get
1252 processed when they become available and not just when the loop is 1450 processed when they become available and not just when the loop is
… …
1260 Event->io (fd => IO::AIO::poll_fileno, 1458 Event->io (fd => IO::AIO::poll_fileno,
1261 poll => 'r', async => 1, 1459 poll => 'r', async => 1,
1262 cb => \&IO::AIO::poll_cb); 1460 cb => \&IO::AIO::poll_cb);
1263 1461
1264 IO::AIO::poll_wait 1462 IO::AIO::poll_wait
1265 If there are any outstanding requests and none of them in the result 1463 Wait until either at least one request is in the result phase or no
1266 phase, wait till the result filehandle becomes ready for reading 1464 requests are outstanding anymore.
1267 (simply does a "select" on the filehandle. This is useful if you 1465
1268 want to synchronously wait for some requests to finish). 1466 This is useful if you want to synchronously wait for some requests
1467 to become ready, without actually handling them.
1269 1468
1270 See "nreqs" for an example. 1469 See "nreqs" for an example.
1271 1470
1272 IO::AIO::poll 1471 IO::AIO::poll
1273 Waits until some requests have been handled. 1472 Waits until some requests have been handled.
… …
1282 1481
1283 Strictly equivalent to: 1482 Strictly equivalent to:
1284 1483
1285 IO::AIO::poll_wait, IO::AIO::poll_cb 1484 IO::AIO::poll_wait, IO::AIO::poll_cb
1286 while IO::AIO::nreqs; 1485 while IO::AIO::nreqs;
1486
1487 This function can be useful at program aborts, to make sure
1488 outstanding I/O has been done ("IO::AIO" uses an "END" block which
1489 already calls this function on normal exits), or when you are merely
1490 using "IO::AIO" for its more advanced functions, rather than for
1491 async I/O, e.g.:
1492
1493 my ($dirs, $nondirs);
1494 IO::AIO::aio_scandir "/tmp", 0, sub { ($dirs, $nondirs) = @_ };
1495 IO::AIO::flush;
1496 # $dirs, $nondirs are now set
1287 1497
1288 IO::AIO::max_poll_reqs $nreqs 1498 IO::AIO::max_poll_reqs $nreqs
1289 IO::AIO::max_poll_time $seconds 1499 IO::AIO::max_poll_time $seconds
1290 These set the maximum number of requests (default 0, meaning 1500 These set the maximum number of requests (default 0, meaning
1291 infinity) that are being processed by "IO::AIO::poll_cb" in one 1501 infinity) that are being processed by "IO::AIO::poll_cb" in one
… …
1385 1595
1386 This is a very bad function to use in interactive programs because 1596 This is a very bad function to use in interactive programs because
1387 it blocks, and a bad way to reduce concurrency because it is 1597 it blocks, and a bad way to reduce concurrency because it is
1388 inexact: Better use an "aio_group" together with a feed callback. 1598 inexact: Better use an "aio_group" together with a feed callback.
1389 1599
1390 It's main use is in scripts without an event loop - when you want to 1600 Its main use is in scripts without an event loop - when you want to
1391 stat a lot of files, you can write somehting like this: 1601 stat a lot of files, you can write something like this:
1392 1602
1393 IO::AIO::max_outstanding 32; 1603 IO::AIO::max_outstanding 32;
1394 1604
1395 for my $path (...) { 1605 for my $path (...) {
1396 aio_stat $path , ...; 1606 aio_stat $path , ...;
… …
1425 1635
1426 IO::AIO::npending 1636 IO::AIO::npending
1427 Returns the number of requests currently in the pending state 1637 Returns the number of requests currently in the pending state
1428 (executed, but not yet processed by poll_cb). 1638 (executed, but not yet processed by poll_cb).
1429 1639
1640 SUBSECOND STAT TIME ACCESS
1641 Both "aio_stat"/"aio_lstat" and perl's "stat"/"lstat" functions can
1642 generally find access/modification and change times with subsecond time
1643 accuracy of the system supports it, but perl's built-in functions only
1644 return the integer part.
1645
1646 The following functions return the timestamps of the most recent stat
1647 with subsecond precision on most systems and work both after
1648 "aio_stat"/"aio_lstat" and perl's "stat"/"lstat" calls. Their return
1649 value is only meaningful after a successful "stat"/"lstat" call, or
1650 during/after a successful "aio_stat"/"aio_lstat" callback.
1651
1652 This is similar to the Time::HiRes "stat" functions, but can return full
1653 resolution without rounding and work with standard perl "stat",
1654 alleviating the need to call the special "Time::HiRes" functions, which
1655 do not act like their perl counterparts.
1656
1657 On operating systems or file systems where subsecond time resolution is
1658 not supported or could not be detected, a fractional part of 0 is
1659 returned, so it is always safe to call these functions.
1660
1661 $seconds = IO::AIO::st_atime, IO::AIO::st_mtime, IO::AIO::st_ctime,
1662 IO::AIO::st_btime
1663 Return the access, modication, change or birth time, respectively,
1664 including fractional part. Due to the limited precision of floating
1665 point, the accuracy on most platforms is only a bit better than
1666 milliseconds for times around now - see the *nsec* function family,
1667 below, for full accuracy.
1668
1669 File birth time is only available when the OS and perl support it
1670 (on FreeBSD and NetBSD at the time of this writing, although support
1671 is adaptive, so if your OS/perl gains support, IO::AIO can take
1672 advantage of it). On systems where it isn't available, 0 is
1673 currently returned, but this might change to "undef" in a future
1674 version.
1675
1676 ($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtime
1677 Returns access, modification, change and birth time all in one go,
1678 and maybe more times in the future version.
1679
1680 $nanoseconds = IO::AIO::st_atimensec, IO::AIO::st_mtimensec,
1681 IO::AIO::st_ctimensec, IO::AIO::st_btimensec
1682 Return the fractional access, modifcation, change or birth time, in
1683 nanoseconds, as an integer in the range 0 to 999999999.
1684
1685 Note that no accessors are provided for access, modification and
1686 change times - you need to get those from "stat _" if required ("int
1687 IO::AIO::st_atime" and so on will *not* generally give you the
1688 correct value).
1689
1690 $seconds = IO::AIO::st_btimesec
1691 The (integral) seconds part of the file birth time, if available.
1692
1693 ($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtimensec
1694 Like the functions above, but returns all four times in one go (and
1695 maybe more in future versions).
1696
1697 $counter = IO::AIO::st_gen
1698 Returns the generation counter (in practice this is just a random
1699 number) of the file. This is only available on platforms which have
1700 this member in their "struct stat" (most BSDs at the time of this
1701 writing) and generally only to the root usert. If unsupported, 0 is
1702 returned, but this might change to "undef" in a future version.
1703
1704 Example: print the high resolution modification time of /etc, using
1705 "stat", and "IO::AIO::aio_stat".
1706
1707 if (stat "/etc") {
1708 printf "stat(/etc) mtime: %f\n", IO::AIO::st_mtime;
1709 }
1710
1711 IO::AIO::aio_stat "/etc", sub {
1712 $_[0]
1713 and return;
1714
1715 printf "aio_stat(/etc) mtime: %d.%09d\n", (stat _)[9], IO::AIO::st_mtimensec;
1716 };
1717
1718 IO::AIO::flush;
1719
1720 Output of the awbove on my system, showing reduced and full accuracy:
1721
1722 stat(/etc) mtime: 1534043702.020808
1723 aio_stat(/etc) mtime: 1534043702.020807792
1724
1430 MISCELLANEOUS FUNCTIONS 1725 MISCELLANEOUS FUNCTIONS
1431 IO::AIO implements some functions that might be useful, but are not 1726 IO::AIO implements some functions that are useful when you want to use
1432 asynchronous. 1727 some "Advanced I/O" function not available to in Perl, without going the
1728 "Asynchronous I/O" route. Many of these have an asynchronous "aio_*"
1729 counterpart.
1730
1731 $numfd = IO::AIO::get_fdlimit
1732 Tries to find the current file descriptor limit and returns it, or
1733 "undef" and sets $! in case of an error. The limit is one larger
1734 than the highest valid file descriptor number.
1735
1736 IO::AIO::min_fdlimit [$numfd]
1737 Try to increase the current file descriptor limit(s) to at least
1738 $numfd by changing the soft or hard file descriptor resource limit.
1739 If $numfd is missing, it will try to set a very high limit, although
1740 this is not recommended when you know the actual minimum that you
1741 require.
1742
1743 If the limit cannot be raised enough, the function makes a
1744 best-effort attempt to increase the limit as much as possible, using
1745 various tricks, while still failing. You can query the resulting
1746 limit using "IO::AIO::get_fdlimit".
1747
1748 If an error occurs, returns "undef" and sets $!, otherwise returns
1749 true.
1433 1750
1434 IO::AIO::sendfile $ofh, $ifh, $offset, $count 1751 IO::AIO::sendfile $ofh, $ifh, $offset, $count
1435 Calls the "eio_sendfile_sync" function, which is like 1752 Calls the "eio_sendfile_sync" function, which is like
1436 "aio_sendfile", but is blocking (this makes most sense if you know 1753 "aio_sendfile", but is blocking (this makes most sense if you know
1437 the input data is likely cached already and the output filehandle is 1754 the input data is likely cached already and the output filehandle is
… …
1454 details). The following advice constants are available: 1771 details). The following advice constants are available:
1455 "IO::AIO::MADV_NORMAL", "IO::AIO::MADV_SEQUENTIAL", 1772 "IO::AIO::MADV_NORMAL", "IO::AIO::MADV_SEQUENTIAL",
1456 "IO::AIO::MADV_RANDOM", "IO::AIO::MADV_WILLNEED", 1773 "IO::AIO::MADV_RANDOM", "IO::AIO::MADV_WILLNEED",
1457 "IO::AIO::MADV_DONTNEED". 1774 "IO::AIO::MADV_DONTNEED".
1458 1775
1776 If $offset is negative, counts from the end. If $length is negative,
1777 the remaining length of the $scalar is used. If possible, $length
1778 will be reduced to fit into the $scalar.
1779
1459 On systems that do not implement "posix_madvise", this function 1780 On systems that do not implement "posix_madvise", this function
1460 returns ENOSYS, otherwise the return value of "posix_madvise". 1781 returns ENOSYS, otherwise the return value of "posix_madvise".
1461 1782
1462 IO::AIO::mprotect $scalar, $offset, $len, $protect 1783 IO::AIO::mprotect $scalar, $offset, $len, $protect
1463 Simply calls the "mprotect" function on the preferably AIO::mmap'ed 1784 Simply calls the "mprotect" function on the preferably AIO::mmap'ed
1464 $scalar (see its manpage for details). The following protect 1785 $scalar (see its manpage for details). The following protect
1465 constants are available: "IO::AIO::PROT_NONE", "IO::AIO::PROT_READ", 1786 constants are available: "IO::AIO::PROT_NONE", "IO::AIO::PROT_READ",
1466 "IO::AIO::PROT_WRITE", "IO::AIO::PROT_EXEC". 1787 "IO::AIO::PROT_WRITE", "IO::AIO::PROT_EXEC".
1467 1788
1789 If $offset is negative, counts from the end. If $length is negative,
1790 the remaining length of the $scalar is used. If possible, $length
1791 will be reduced to fit into the $scalar.
1792
1468 On systems that do not implement "mprotect", this function returns 1793 On systems that do not implement "mprotect", this function returns
1469 ENOSYS, otherwise the return value of "mprotect". 1794 ENOSYS, otherwise the return value of "mprotect".
1470 1795
1471 IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset] 1796 IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1472 Memory-maps a file (or anonymous memory range) and attaches it to 1797 Memory-maps a file (or anonymous memory range) and attaches it to
1473 the given $scalar, which will act like a string scalar. 1798 the given $scalar, which will act like a string scalar. Returns true
1799 on success, and false otherwise.
1474 1800
1801 The scalar must exist, but its contents do not matter - this means
1802 you cannot use a nonexistant array or hash element. When in doubt,
1803 "undef" the scalar first.
1804
1475 The only operations allowed on the scalar are "substr"/"vec" that 1805 The only operations allowed on the mmapped scalar are
1476 don't change the string length, and most read-only operations such 1806 "substr"/"vec", which don't change the string length, and most
1477 as copying it or searching it with regexes and so on. 1807 read-only operations such as copying it or searching it with regexes
1808 and so on.
1478 1809
1479 Anything else is unsafe and will, at best, result in memory leaks. 1810 Anything else is unsafe and will, at best, result in memory leaks.
1480 1811
1481 The memory map associated with the $scalar is automatically removed 1812 The memory map associated with the $scalar is automatically removed
1482 when the $scalar is destroyed, or when the "IO::AIO::mmap" or 1813 when the $scalar is undef'd or destroyed, or when the
1483 "IO::AIO::munmap" functions are called. 1814 "IO::AIO::mmap" or "IO::AIO::munmap" functions are called on it.
1484 1815
1485 This calls the "mmap"(2) function internally. See your system's 1816 This calls the "mmap"(2) function internally. See your system's
1486 manual page for details on the $length, $prot and $flags parameters. 1817 manual page for details on the $length, $prot and $flags parameters.
1487 1818
1488 The $length must be larger than zero and smaller than the actual 1819 The $length must be larger than zero and smaller than the actual
… …
1492 "IO::AIO::PROT_EXEC", "IO::AIO::PROT_READ" and/or 1823 "IO::AIO::PROT_EXEC", "IO::AIO::PROT_READ" and/or
1493 "IO::AIO::PROT_WRITE", 1824 "IO::AIO::PROT_WRITE",
1494 1825
1495 $flags can be a combination of "IO::AIO::MAP_SHARED" or 1826 $flags can be a combination of "IO::AIO::MAP_SHARED" or
1496 "IO::AIO::MAP_PRIVATE", or a number of system-specific flags (when 1827 "IO::AIO::MAP_PRIVATE", or a number of system-specific flags (when
1497 not available, the are defined as 0): "IO::AIO::MAP_ANONYMOUS" 1828 not available, the are 0): "IO::AIO::MAP_ANONYMOUS" (which is set to
1498 (which is set to "MAP_ANON" if your system only provides this 1829 "MAP_ANON" if your system only provides this constant),
1830 "IO::AIO::MAP_LOCKED", "IO::AIO::MAP_NORESERVE",
1499 constant), "IO::AIO::MAP_HUGETLB", "IO::AIO::MAP_LOCKED", 1831 "IO::AIO::MAP_POPULATE", "IO::AIO::MAP_NONBLOCK",
1500 "IO::AIO::MAP_NORESERVE", "IO::AIO::MAP_POPULATE" or 1832 "IO::AIO::MAP_FIXED", "IO::AIO::MAP_GROWSDOWN",
1501 "IO::AIO::MAP_NONBLOCK" 1833 "IO::AIO::MAP_32BIT", "IO::AIO::MAP_HUGETLB", "IO::AIO::MAP_STACK",
1834 "IO::AIO::MAP_FIXED_NOREPLACE", "IO::AIO::MAP_SHARED_VALIDATE",
1835 "IO::AIO::MAP_SYNC" or "IO::AIO::MAP_UNINITIALIZED".
1502 1836
1503 If $fh is "undef", then a file descriptor of -1 is passed. 1837 If $fh is "undef", then a file descriptor of -1 is passed.
1504 1838
1505 $offset is the offset from the start of the file - it generally must 1839 $offset is the offset from the start of the file - it generally must
1506 be a multiple of "IO::AIO::PAGESIZE" and defaults to 0. 1840 be a multiple of "IO::AIO::PAGESIZE" and defaults to 0.
… …
1518 1852
1519 my $fast_md5 = md5 $data; 1853 my $fast_md5 = md5 $data;
1520 1854
1521 IO::AIO::munmap $scalar 1855 IO::AIO::munmap $scalar
1522 Removes a previous mmap and undefines the $scalar. 1856 Removes a previous mmap and undefines the $scalar.
1857
1858 IO::AIO::mremap $scalar, $new_length, $flags = MREMAP_MAYMOVE[,
1859 $new_address = 0]
1860 Calls the Linux-specific mremap(2) system call. The $scalar must
1861 have been mapped by "IO::AIO::mmap", and $flags must currently
1862 either be 0 or "IO::AIO::MREMAP_MAYMOVE".
1863
1864 Returns true if successful, and false otherwise. If the underlying
1865 mmapped region has changed address, then the true value has the
1866 numerical value 1, otherwise it has the numerical value 0:
1867
1868 my $success = IO::AIO::mremap $mmapped, 8192, IO::AIO::MREMAP_MAYMOVE
1869 or die "mremap: $!";
1870
1871 if ($success*1) {
1872 warn "scalar has chanegd address in memory\n";
1873 }
1874
1875 "IO::AIO::MREMAP_FIXED" and the $new_address argument are currently
1876 implemented, but not supported and might go away in a future
1877 version.
1878
1879 On systems where this call is not supported or is not emulated, this
1880 call returns falls and sets $! to "ENOSYS".
1881
1882 IO::AIO::mlockall $flags
1883 Calls the "eio_mlockall_sync" function, which is like
1884 "aio_mlockall", but is blocking.
1523 1885
1524 IO::AIO::munlock $scalar, $offset = 0, $length = undef 1886 IO::AIO::munlock $scalar, $offset = 0, $length = undef
1525 Calls the "munlock" function, undoing the effects of a previous 1887 Calls the "munlock" function, undoing the effects of a previous
1526 "aio_mlock" call (see its description for details). 1888 "aio_mlock" call (see its description for details).
1527 1889
1528 IO::AIO::munlockall 1890 IO::AIO::munlockall
1529 Calls the "munlockall" function. 1891 Calls the "munlockall" function.
1530 1892
1531 On systems that do not implement "munlockall", this function returns 1893 On systems that do not implement "munlockall", this function returns
1532 ENOSYS, otherwise the return value of "munlockall". 1894 ENOSYS, otherwise the return value of "munlockall".
1895
1896 $fh = IO::AIO::accept4 $r_fh, $sockaddr, $sockaddr_maxlen, $flags
1897 Uses the GNU/Linux accept4(2) syscall, if available, to accept a
1898 socket and return the new file handle on success, or sets $! and
1899 returns "undef" on error.
1900
1901 The remote name of the new socket will be stored in $sockaddr, which
1902 will be extended to allow for at least $sockaddr_maxlen octets. If
1903 the socket name does not fit into $sockaddr_maxlen octets, this is
1904 signaled by returning a longer string in $sockaddr, which might or
1905 might not be truncated.
1906
1907 To accept name-less sockets, use "undef" for $sockaddr and 0 for
1908 $sockaddr_maxlen.
1909
1910 The main reasons to use this syscall rather than portable accept(2)
1911 are that you can specify "SOCK_NONBLOCK" and/or "SOCK_CLOEXEC" flags
1912 and you can accept name-less sockets by specifying 0 for
1913 $sockaddr_maxlen, which is sadly not possible with perl's interface
1914 to "accept".
1915
1916 IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
1917 Calls the GNU/Linux splice(2) syscall, if available. If $r_off or
1918 $w_off are "undef", then "NULL" is passed for these, otherwise they
1919 should be the file offset.
1920
1921 $r_fh and $w_fh should not refer to the same file, as splice might
1922 silently corrupt the data in this case.
1923
1924 The following symbol flag values are available:
1925 "IO::AIO::SPLICE_F_MOVE", "IO::AIO::SPLICE_F_NONBLOCK",
1926 "IO::AIO::SPLICE_F_MORE" and "IO::AIO::SPLICE_F_GIFT".
1927
1928 See the splice(2) manpage for details.
1929
1930 IO::AIO::tee $r_fh, $w_fh, $length, $flags
1931 Calls the GNU/Linux tee(2) syscall, see its manpage and the
1932 description for "IO::AIO::splice" above for details.
1933
1934 $actual_size = IO::AIO::pipesize $r_fh[, $new_size]
1935 Attempts to query or change the pipe buffer size. Obviously works
1936 only on pipes, and currently works only on GNU/Linux systems, and
1937 fails with -1/"ENOSYS" everywhere else. If anybody knows how to
1938 influence pipe buffer size on other systems, drop me a note.
1939
1940 ($rfh, $wfh) = IO::AIO::pipe2 [$flags]
1941 This is a direct interface to the Linux pipe2(2) system call. If
1942 $flags is missing or 0, then this should be the same as a call to
1943 perl's built-in "pipe" function and create a new pipe, and works on
1944 systems that lack the pipe2 syscall. On win32, this case invokes
1945 "_pipe (..., 4096, O_BINARY)".
1946
1947 If $flags is non-zero, it tries to invoke the pipe2 system call with
1948 the given flags (Linux 2.6.27, glibc 2.9).
1949
1950 On success, the read and write file handles are returned.
1951
1952 On error, nothing will be returned. If the pipe2 syscall is missing
1953 and $flags is non-zero, fails with "ENOSYS".
1954
1955 Please refer to pipe2(2) for more info on the $flags, but at the
1956 time of this writing, "IO::AIO::O_CLOEXEC", "IO::AIO::O_NONBLOCK"
1957 and "IO::AIO::O_DIRECT" (Linux 3.4, for packet-based pipes) were
1958 supported.
1959
1960 Example: create a pipe race-free w.r.t. threads and fork:
1961
1962 my ($rfh, $wfh) = IO::AIO::pipe2 IO::AIO::O_CLOEXEC
1963 or die "pipe2: $!\n";
1964
1965 $fh = IO::AIO::memfd_create $pathname[, $flags]
1966 This is a direct interface to the Linux memfd_create(2) system call.
1967 The (unhelpful) default for $flags is 0, but your default should be
1968 "IO::AIO::MFD_CLOEXEC".
1969
1970 On success, the new memfd filehandle is returned, otherwise returns
1971 "undef". If the memfd_create syscall is missing, fails with
1972 "ENOSYS".
1973
1974 Please refer to memfd_create(2) for more info on this call.
1975
1976 The following $flags values are available: "IO::AIO::MFD_CLOEXEC",
1977 "IO::AIO::MFD_ALLOW_SEALING" and "IO::AIO::MFD_HUGETLB".
1978
1979 Example: create a new memfd.
1980
1981 my $fh = IO::AIO::memfd_create "somenameforprocfd", IO::AIO::MFD_CLOEXEC
1982 or die "memfd_create: $!\n";
1983
1984 $fh = IO::AIO::pidfd_open $pid[, $flags]
1985 This is an interface to the Linux pidfd_open(2) system call. The
1986 default for $flags is 0.
1987
1988 On success, a new pidfd filehandle is returned (that is already set
1989 to close-on-exec), otherwise returns "undef". If the syscall is
1990 missing, fails with "ENOSYS".
1991
1992 Example: open pid 6341 as pidfd.
1993
1994 my $fh = IO::AIO::pidfd_open 6341
1995 or die "pidfd_open: $!\n";
1996
1997 $status = IO::AIO::pidfd_send_signal $pidfh, $signal[, $siginfo[,
1998 $flags]]
1999 This is an interface to the Linux pidfd_send_signal system call. The
2000 default for $siginfo is "undef" and the default for $flags is 0.
2001
2002 Returns the system call status. If the syscall is missing, fails
2003 with "ENOSYS".
2004
2005 When specified, $siginfo must be a reference to a hash with one or
2006 more of the following members:
2007
2008 code - the "si_code" member
2009 pid - the "si_pid" member
2010 uid - the "si_uid" member
2011 value_int - the "si_value.sival_int" member
2012 value_ptr - the "si_value.sival_ptr" member, specified as an integer
2013
2014 Example: send a SIGKILL to the specified process.
2015
2016 my $status = IO::AIO::pidfd_send_signal $pidfh, 9, undef
2017 and die "pidfd_send_signal: $!\n";
2018
2019 Example: send a SIGKILL to the specified process with extra data.
2020
2021 my $status = IO::AIO::pidfd_send_signal $pidfh, 9, { code => -1, value_int => 7 }
2022 and die "pidfd_send_signal: $!\n";
2023
2024 $fh = IO::AIO::pidfd_getfd $pidfh, $targetfd[, $flags]
2025 This is an interface to the Linux pidfd_getfd system call. The
2026 default for $flags is 0.
2027
2028 On success, returns a dup'ed copy of the target file descriptor
2029 (specified as an integer) returned (that is already set to
2030 close-on-exec), otherwise returns "undef". If the syscall is
2031 missing, fails with "ENOSYS".
2032
2033 Example: get a copy of standard error of another process and print
2034 soemthing to it.
2035
2036 my $errfh = IO::AIO::pidfd_getfd $pidfh, 2
2037 or die "pidfd_getfd: $!\n";
2038 print $errfh "stderr\n";
2039
2040 $fh = IO::AIO::eventfd [$initval, [$flags]]
2041 This is a direct interface to the Linux eventfd(2) system call. The
2042 (unhelpful) defaults for $initval and $flags are 0 for both.
2043
2044 On success, the new eventfd filehandle is returned, otherwise
2045 returns "undef". If the eventfd syscall is missing, fails with
2046 "ENOSYS".
2047
2048 Please refer to eventfd(2) for more info on this call.
2049
2050 The following symbol flag values are available:
2051 "IO::AIO::EFD_CLOEXEC", "IO::AIO::EFD_NONBLOCK" and
2052 "IO::AIO::EFD_SEMAPHORE" (Linux 2.6.30).
2053
2054 Example: create a new eventfd filehandle:
2055
2056 $fh = IO::AIO::eventfd 0, IO::AIO::EFD_CLOEXEC
2057 or die "eventfd: $!\n";
2058
2059 $fh = IO::AIO::timerfd_create $clockid[, $flags]
2060 This is a direct interface to the Linux timerfd_create(2) system
2061 call. The (unhelpful) default for $flags is 0, but your default
2062 should be "IO::AIO::TFD_CLOEXEC".
2063
2064 On success, the new timerfd filehandle is returned, otherwise
2065 returns "undef". If the timerfd_create syscall is missing, fails
2066 with "ENOSYS".
2067
2068 Please refer to timerfd_create(2) for more info on this call.
2069
2070 The following $clockid values are available:
2071 "IO::AIO::CLOCK_REALTIME", "IO::AIO::CLOCK_MONOTONIC"
2072 "IO::AIO::CLOCK_CLOCK_BOOTTIME" (Linux 3.15)
2073 "IO::AIO::CLOCK_CLOCK_REALTIME_ALARM" (Linux 3.11) and
2074 "IO::AIO::CLOCK_CLOCK_BOOTTIME_ALARM" (Linux 3.11).
2075
2076 The following $flags values are available (Linux 2.6.27):
2077 "IO::AIO::TFD_NONBLOCK" and "IO::AIO::TFD_CLOEXEC".
2078
2079 Example: create a new timerfd and set it to one-second repeated
2080 alarms, then wait for two alarms:
2081
2082 my $fh = IO::AIO::timerfd_create IO::AIO::CLOCK_BOOTTIME, IO::AIO::TFD_CLOEXEC
2083 or die "timerfd_create: $!\n";
2084
2085 defined IO::AIO::timerfd_settime $fh, 0, 1, 1
2086 or die "timerfd_settime: $!\n";
2087
2088 for (1..2) {
2089 8 == sysread $fh, my $buf, 8
2090 or die "timerfd read failure\n";
2091
2092 printf "number of expirations (likely 1): %d\n",
2093 unpack "Q", $buf;
2094 }
2095
2096 ($cur_interval, $cur_value) = IO::AIO::timerfd_settime $fh, $flags,
2097 $new_interval, $nbw_value
2098 This is a direct interface to the Linux timerfd_settime(2) system
2099 call. Please refer to its manpage for more info on this call.
2100
2101 The new itimerspec is specified using two (possibly fractional)
2102 second values, $new_interval and $new_value).
2103
2104 On success, the current interval and value are returned (as per
2105 "timerfd_gettime"). On failure, the empty list is returned.
2106
2107 The following $flags values are available:
2108 "IO::AIO::TFD_TIMER_ABSTIME" and "IO::AIO::TFD_TIMER_CANCEL_ON_SET".
2109
2110 See "IO::AIO::timerfd_create" for a full example.
2111
2112 ($cur_interval, $cur_value) = IO::AIO::timerfd_gettime $fh
2113 This is a direct interface to the Linux timerfd_gettime(2) system
2114 call. Please refer to its manpage for more info on this call.
2115
2116 On success, returns the current values of interval and value for the
2117 given timerfd (as potentially fractional second values). On failure,
2118 the empty list is returned.
1533 2119
1534EVENT LOOP INTEGRATION 2120EVENT LOOP INTEGRATION
1535 It is recommended to use AnyEvent::AIO to integrate IO::AIO 2121 It is recommended to use AnyEvent::AIO to integrate IO::AIO
1536 automatically into many event loops: 2122 automatically into many event loops:
1537 2123
… …
1587 forking, if "IO::AIO" was used in the parent. Calling it while 2173 forking, if "IO::AIO" was used in the parent. Calling it while
1588 IO::AIO is active in the process will result in undefined behaviour. 2174 IO::AIO is active in the process will result in undefined behaviour.
1589 Calling it at any time will also result in any undefined (by POSIX) 2175 Calling it at any time will also result in any undefined (by POSIX)
1590 behaviour. 2176 behaviour.
1591 2177
2178 LINUX-SPECIFIC CALLS
2179 When a call is documented as "linux-specific" then this means it
2180 originated on GNU/Linux. "IO::AIO" will usually try to autodetect the
2181 availability and compatibility of such calls regardless of the platform
2182 it is compiled on, so platforms such as FreeBSD which often implement
2183 these calls will work. When in doubt, call them and see if they fail wth
2184 "ENOSYS".
2185
1592 MEMORY USAGE 2186 MEMORY USAGE
1593 Per-request usage: 2187 Per-request usage:
1594 2188
1595 Each aio request uses - depending on your architecture - around 100-200 2189 Each aio request uses - depending on your architecture - around 100-200
1596 bytes of memory. In addition, stat requests need a stat buffer (possibly 2190 bytes of memory. In addition, stat requests need a stat buffer (possibly
… …
1606 In the execution phase, some aio requests require more memory for 2200 In the execution phase, some aio requests require more memory for
1607 temporary buffers, and each thread requires a stack and other data 2201 temporary buffers, and each thread requires a stack and other data
1608 structures (usually around 16k-128k, depending on the OS). 2202 structures (usually around 16k-128k, depending on the OS).
1609 2203
1610KNOWN BUGS 2204KNOWN BUGS
1611 Known bugs will be fixed in the next release. 2205 Known bugs will be fixed in the next release :)
2206
2207KNOWN ISSUES
2208 Calls that try to "import" foreign memory areas (such as "IO::AIO::mmap"
2209 or "IO::AIO::aio_slurp") do not work with generic lvalues, such as
2210 non-created hash slots or other scalars I didn't think of. It's best to
2211 avoid such and either use scalar variables or making sure that the
2212 scalar exists (e.g. by storing "undef") and isn't "funny" (e.g. tied).
2213
2214 I am not sure anything can be done about this, so this is considered a
2215 known issue, rather than a bug.
1612 2216
1613SEE ALSO 2217SEE ALSO
1614 AnyEvent::AIO for easy integration into event loops, Coro::AIO for a 2218 AnyEvent::AIO for easy integration into event loops, Coro::AIO for a
1615 more natural syntax. 2219 more natural syntax and IO::FDPass for file descriptor passing.
1616 2220
1617AUTHOR 2221AUTHOR
1618 Marc Lehmann <schmorp@schmorp.de> 2222 Marc Lehmann <schmorp@schmorp.de>
1619 http://home.schmorp.de/ 2223 http://home.schmorp.de/
1620 2224

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