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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.274 by root, Thu Sep 21 23:43:46 2017 UTC vs.
Revision 1.292 by root, Tue Aug 14 09:29:50 2018 UTC

171use common::sense; 171use common::sense;
172 172
173use base 'Exporter'; 173use base 'Exporter';
174 174
175BEGIN { 175BEGIN {
176 our $VERSION = 4.35; 176 our $VERSION = 4.53;
177 177
178 our @AIO_REQ = qw(aio_sendfile aio_seek aio_read aio_write aio_open aio_close 178 our @AIO_REQ = qw(aio_sendfile aio_seek aio_read aio_write aio_open aio_close
179 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
180 aio_scandir aio_symlink aio_readlink aio_realpath aio_fcntl aio_ioctl 180 aio_scandir aio_symlink aio_readlink aio_realpath aio_fcntl aio_ioctl
181 aio_sync aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range 181 aio_sync aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range
183 aio_rename aio_rename2 aio_link aio_move aio_copy aio_group 183 aio_rename aio_rename2 aio_link aio_move aio_copy aio_group
184 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
185 aio_chmod aio_utime aio_truncate 185 aio_chmod aio_utime aio_truncate
186 aio_msync aio_mtouch aio_mlock aio_mlockall 186 aio_msync aio_mtouch aio_mlock aio_mlockall
187 aio_statvfs 187 aio_statvfs
188 aio_slurp
188 aio_wd); 189 aio_wd);
189 190
190 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice)); 191 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
191 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush 192 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
192 min_parallel max_parallel max_idle idle_timeout 193 min_parallel max_parallel max_idle idle_timeout
193 nreqs nready npending nthreads 194 nreqs nready npending nthreads
194 max_poll_time max_poll_reqs 195 max_poll_time max_poll_reqs
195 sendfile fadvise madvise 196 sendfile fadvise madvise
196 mmap munmap munlock munlockall); 197 mmap munmap mremap munlock munlockall);
197 198
198 push @AIO_REQ, qw(aio_busy); # not exported 199 push @AIO_REQ, qw(aio_busy); # not exported
199 200
200 @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; 201 @IO::AIO::GRP::ISA = 'IO::AIO::REQ';
201 202
277 IO::AIO::idle_timeout $seconds 278 IO::AIO::idle_timeout $seconds
278 IO::AIO::max_outstanding $maxreqs 279 IO::AIO::max_outstanding $maxreqs
279 IO::AIO::nreqs 280 IO::AIO::nreqs
280 IO::AIO::nready 281 IO::AIO::nready
281 IO::AIO::npending 282 IO::AIO::npending
283 $nfd = IO::AIO::get_fdlimit [EXPERIMENTAL]
284 IO::AIO::min_fdlimit $nfd [EXPERIMENTAL]
282 285
283 IO::AIO::sendfile $ofh, $ifh, $offset, $count 286 IO::AIO::sendfile $ofh, $ifh, $offset, $count
284 IO::AIO::fadvise $fh, $offset, $len, $advice 287 IO::AIO::fadvise $fh, $offset, $len, $advice
285 IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]] 288 IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
286 IO::AIO::munmap $scalar 289 IO::AIO::munmap $scalar
290 IO::AIO::mremap $scalar, $new_length, $flags[, $new_address]
287 IO::AIO::madvise $scalar, $offset, $length, $advice 291 IO::AIO::madvise $scalar, $offset, $length, $advice
288 IO::AIO::mprotect $scalar, $offset, $length, $protect 292 IO::AIO::mprotect $scalar, $offset, $length, $protect
289 IO::AIO::munlock $scalar, $offset = 0, $length = undef 293 IO::AIO::munlock $scalar, $offset = 0, $length = undef
290 IO::AIO::munlockall 294 IO::AIO::munlockall
291 295
401following POSIX and non-POSIX constants are available (missing ones on 405following POSIX and non-POSIX constants are available (missing ones on
402your system are, as usual, C<0>): 406your system are, as usual, C<0>):
403 407
404C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>, 408C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,
405C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>, 409C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,
406C<O_RSYNC>, C<O_SYNC>, C<O_PATH>, C<O_TMPFILE>, and C<O_TTY_INIT>. 410C<O_RSYNC>, C<O_SYNC>, C<O_PATH>, C<O_TMPFILE>, C<O_TTY_INIT> and C<O_ACCMODE>.
407 411
408 412
409=item aio_close $fh, $callback->($status) 413=item aio_close $fh, $callback->($status)
410 414
411Asynchronously close a file and call the callback with the result 415Asynchronously close a file and call the callback with the result
556behaviour). 560behaviour).
557 561
558C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>, 562C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>,
559C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>, 563C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>,
560C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>. 564C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>.
565
566To access higher resolution stat timestamps, see L<SUBSECOND STAT TIME
567ACCESS>.
561 568
562Example: Print the length of F</etc/passwd>: 569Example: Print the length of F</etc/passwd>:
563 570
564 aio_stat "/etc/passwd", sub { 571 aio_stat "/etc/passwd", sub {
565 $_[0] and die "stat failed: $!"; 572 $_[0] and die "stat failed: $!";
609 namemax => 255, 616 namemax => 255,
610 frsize => 1024, 617 frsize => 1024,
611 fsid => 1810 618 fsid => 1810
612 } 619 }
613 620
614Here is a (likely partial - send me updates!) list of fsid values used by
615Linux - it is safe to hardcode these when C<$^O> is C<linux>:
616
617 0x0000adf5 adfs
618 0x0000adff affs
619 0x5346414f afs
620 0x09041934 anon-inode filesystem
621 0x00000187 autofs
622 0x42465331 befs
623 0x1badface bfs
624 0x42494e4d binfmt_misc
625 0x9123683e btrfs
626 0x0027e0eb cgroupfs
627 0xff534d42 cifs
628 0x73757245 coda
629 0x012ff7b7 coh
630 0x28cd3d45 cramfs
631 0x453dcd28 cramfs-wend (wrong endianness)
632 0x64626720 debugfs
633 0x00001373 devfs
634 0x00001cd1 devpts
635 0x0000f15f ecryptfs
636 0x00414a53 efs
637 0x0000137d ext
638 0x0000ef53 ext2/ext3/ext4
639 0x0000ef51 ext2
640 0xf2f52010 f2fs
641 0x00004006 fat
642 0x65735546 fuseblk
643 0x65735543 fusectl
644 0x0bad1dea futexfs
645 0x01161970 gfs2
646 0x47504653 gpfs
647 0x00004244 hfs
648 0xf995e849 hpfs
649 0x00c0ffee hostfs
650 0x958458f6 hugetlbfs
651 0x2bad1dea inotifyfs
652 0x00009660 isofs
653 0x000072b6 jffs2
654 0x3153464a jfs
655 0x6b414653 k-afs
656 0x0bd00bd0 lustre
657 0x0000137f minix
658 0x0000138f minix 30 char names
659 0x00002468 minix v2
660 0x00002478 minix v2 30 char names
661 0x00004d5a minix v3
662 0x19800202 mqueue
663 0x00004d44 msdos
664 0x0000564c novell
665 0x00006969 nfs
666 0x6e667364 nfsd
667 0x00003434 nilfs
668 0x5346544e ntfs
669 0x00009fa1 openprom
670 0x7461636F ocfs2
671 0x00009fa0 proc
672 0x6165676c pstorefs
673 0x0000002f qnx4
674 0x68191122 qnx6
675 0x858458f6 ramfs
676 0x52654973 reiserfs
677 0x00007275 romfs
678 0x67596969 rpc_pipefs
679 0x73636673 securityfs
680 0xf97cff8c selinux
681 0x0000517b smb
682 0x534f434b sockfs
683 0x73717368 squashfs
684 0x62656572 sysfs
685 0x012ff7b6 sysv2
686 0x012ff7b5 sysv4
687 0x01021994 tmpfs
688 0x15013346 udf
689 0x00011954 ufs
690 0x54190100 ufs byteswapped
691 0x00009fa2 usbdevfs
692 0x01021997 v9fs
693 0xa501fcf5 vxfs
694 0xabba1974 xenfs
695 0x012ff7b4 xenix
696 0x58465342 xfs
697 0x012fd16d xia
698
699=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 621=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
700 622
701Works like perl's C<utime> function (including the special case of $atime 623Works like perl's C<utime> function (including the special case of $atime
702and $mtime being undef). Fractional times are supported if the underlying 624and $mtime being undef). Fractional times are supported if the underlying
703syscalls support them. 625syscalls support them.
871 793
872=over 4 794=over 4
873 795
874=item IO::AIO::READDIR_DENTS 796=item IO::AIO::READDIR_DENTS
875 797
876When this flag is off, then the callback gets an arrayref consisting of 798Normally the callback gets an arrayref consisting of names only (as
877names only (as with C<aio_readdir>), otherwise it gets an arrayref with 799with C<aio_readdir>). If this flag is set, then the callback gets an
878C<[$name, $type, $inode]> arrayrefs, each describing a single directory 800arrayref with C<[$name, $type, $inode]> arrayrefs, each describing a
879entry in more detail. 801single directory entry in more detail:
880 802
881C<$name> is the name of the entry. 803C<$name> is the name of the entry.
882 804
883C<$type> is one of the C<IO::AIO::DT_xxx> constants: 805C<$type> is one of the C<IO::AIO::DT_xxx> constants:
884 806
885C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>, 807C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
886C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>, 808C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
887C<IO::AIO::DT_WHT>. 809C<IO::AIO::DT_WHT>.
888 810
889C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to 811C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need
890know, you have to run stat yourself. Also, for speed reasons, the C<$type> 812to know, you have to run stat yourself. Also, for speed/memory reasons,
891scalars are read-only: you can not modify them. 813the C<$type> scalars are read-only: you must not modify them.
892 814
893C<$inode> is the inode number (which might not be exact on systems with 64 815C<$inode> is the inode number (which might not be exact on systems with 64
894bit inode numbers and 32 bit perls). This field has unspecified content on 816bit inode numbers and 32 bit perls). This field has unspecified content on
895systems that do not deliver the inode information. 817systems that do not deliver the inode information.
896 818
907short names are tried first. 829short names are tried first.
908 830
909=item IO::AIO::READDIR_STAT_ORDER 831=item IO::AIO::READDIR_STAT_ORDER
910 832
911When this flag is set, then the names will be returned in an order 833When this flag is set, then the names will be returned in an order
912suitable for stat()'ing each one. That is, when you plan to stat() 834suitable for stat()'ing each one. That is, when you plan to stat() most or
913all files in the given directory, then the returned order will likely 835all files in the given directory, then the returned order will likely be
914be fastest. 836faster.
915 837
916If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then 838If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified,
917the likely dirs come first, resulting in a less optimal stat order. 839then the likely dirs come first, resulting in a less optimal stat order
840for stat'ing all entries, but likely a more optimal order for finding
841subdirectories.
918 842
919=item IO::AIO::READDIR_FOUND_UNKNOWN 843=item IO::AIO::READDIR_FOUND_UNKNOWN
920 844
921This flag should not be set when calling C<aio_readdirx>. Instead, it 845This flag should not be set when calling C<aio_readdirx>. Instead, it
922is being set by C<aio_readdirx>, when any of the C<$type>'s found were 846is being set by C<aio_readdirx>, when any of the C<$type>'s found were
924C<$type>'s are known, which can be used to speed up some algorithms. 848C<$type>'s are known, which can be used to speed up some algorithms.
925 849
926=back 850=back
927 851
928 852
853=item aio_slurp $pathname, $offset, $length, $data, $callback->($status)
854
855Opens, reads and closes the given file. The data is put into C<$data>,
856which is resized as required.
857
858If C<$offset> is negative, then it is counted from the end of the file.
859
860If C<$length> is zero, then the remaining length of the file is
861used. Also, in this case, the same limitations to modifying C<$data> apply
862as when IO::AIO::mmap is used, i.e. it must only be modified in-place
863with C<substr>. If the size of the file is known, specifying a non-zero
864C<$length> results in a performance advantage.
865
866This request is similar to the older C<aio_load> request, but since it is
867a single request, it might be more efficient to use.
868
869Example: load F</etc/passwd> into C<$passwd>.
870
871 my $passwd;
872 aio_slurp "/etc/passwd", 0, 0, $passwd, sub {
873 $_[0] >= 0
874 or die "/etc/passwd: $!\n";
875
876 printf "/etc/passwd is %d bytes long, and contains:\n", length $passwd;
877 print $passwd;
878 };
879 IO::AIO::flush;
880
881
929=item aio_load $pathname, $data, $callback->($status) 882=item aio_load $pathname, $data, $callback->($status)
930 883
931This is a composite request that tries to fully load the given file into 884This is a composite request that tries to fully load the given file into
932memory. Status is the same as with aio_read. 885memory. Status is the same as with aio_read.
886
887Using C<aio_slurp> might be more efficient, as it is a single request.
933 888
934=cut 889=cut
935 890
936sub aio_load($$;$) { 891sub aio_load($$;$) {
937 my ($path, undef, $cb) = @_; 892 my ($path, undef, $cb) = @_;
957=item aio_copy $srcpath, $dstpath, $callback->($status) 912=item aio_copy $srcpath, $dstpath, $callback->($status)
958 913
959Try to copy the I<file> (directories not supported as either source or 914Try to copy the I<file> (directories not supported as either source or
960destination) from C<$srcpath> to C<$dstpath> and call the callback with 915destination) from C<$srcpath> to C<$dstpath> and call the callback with
961a status of C<0> (ok) or C<-1> (error, see C<$!>). 916a status of C<0> (ok) or C<-1> (error, see C<$!>).
917
918Existing destination files will be truncated.
962 919
963This is a composite request that creates the destination file with 920This is a composite request that creates the destination file with
964mode 0200 and copies the contents of the source file into it using 921mode 0200 and copies the contents of the source file into it using
965C<aio_sendfile>, followed by restoring atime, mtime, access mode and 922C<aio_sendfile>, followed by restoring atime, mtime, access mode and
966uid/gid, in that order. 923uid/gid, in that order.
1076Scans a directory (similar to C<aio_readdir>) but additionally tries to 1033Scans a directory (similar to C<aio_readdir>) but additionally tries to
1077efficiently separate the entries of directory C<$path> into two sets of 1034efficiently separate the entries of directory C<$path> into two sets of
1078names, directories you can recurse into (directories), and ones you cannot 1035names, directories you can recurse into (directories), and ones you cannot
1079recurse into (everything else, including symlinks to directories). 1036recurse into (everything else, including symlinks to directories).
1080 1037
1081C<aio_scandir> is a composite request that creates of many sub requests_ 1038C<aio_scandir> is a composite request that generates many sub requests.
1082C<$maxreq> specifies the maximum number of outstanding aio requests that 1039C<$maxreq> specifies the maximum number of outstanding aio requests that
1083this function generates. If it is C<< <= 0 >>, then a suitable default 1040this function generates. If it is C<< <= 0 >>, then a suitable default
1084will be chosen (currently 4). 1041will be chosen (currently 4).
1085 1042
1086On error, the callback is called without arguments, otherwise it receives 1043On error, the callback is called without arguments, otherwise it receives
1479C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>, 1436C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
1480C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>, 1437C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
1481C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or 1438C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
1482C<IO::AIO::FIEMAP_EXTENT_SHARED>. 1439C<IO::AIO::FIEMAP_EXTENT_SHARED>.
1483 1440
1484At the time of this writing (Linux 3.2), this requets is unreliable unless 1441At the time of this writing (Linux 3.2), this request is unreliable unless
1485C<$count> is C<undef>, as the kernel has all sorts of bugs preventing 1442C<$count> is C<undef>, as the kernel has all sorts of bugs preventing
1486it to return all extents of a range for files with large number of 1443it to return all extents of a range for files with a large number of
1487extents. The code works around all these issues if C<$count> is undef. 1444extents. The code (only) works around all these issues if C<$count> is
1445C<undef>.
1488 1446
1489=item aio_group $callback->(...) 1447=item aio_group $callback->(...)
1490 1448
1491This is a very special aio request: Instead of doing something, it is a 1449This is a very special aio request: Instead of doing something, it is a
1492container for other aio requests, which is useful if you want to bundle 1450container for other aio requests, which is useful if you want to bundle
1605There are some caveats: when directories get renamed (or deleted), the 1563There are some caveats: when directories get renamed (or deleted), the
1606pathname string doesn't change, so will point to the new directory (or 1564pathname string doesn't change, so will point to the new directory (or
1607nowhere at all), while the directory fd, if available on the system, 1565nowhere at all), while the directory fd, if available on the system,
1608will still point to the original directory. Most functions accepting a 1566will still point to the original directory. Most functions accepting a
1609pathname will use the directory fd on newer systems, and the string on 1567pathname will use the directory fd on newer systems, and the string on
1610older systems. Some functions (such as realpath) will always rely on the 1568older systems. Some functions (such as C<aio_realpath>) will always rely on
1611string form of the pathname. 1569the string form of the pathname.
1612 1570
1613So this functionality is mainly useful to get some protection against 1571So this functionality is mainly useful to get some protection against
1614C<chdir>, to easily get an absolute path out of a relative path for future 1572C<chdir>, to easily get an absolute path out of a relative path for future
1615reference, and to speed up doing many operations in the same directory 1573reference, and to speed up doing many operations in the same directory
1616(e.g. when stat'ing all files in a directory). 1574(e.g. when stat'ing all files in a directory).
2055Returns the number of requests currently in the pending state (executed, 2013Returns the number of requests currently in the pending state (executed,
2056but not yet processed by poll_cb). 2014but not yet processed by poll_cb).
2057 2015
2058=back 2016=back
2059 2017
2018=head3 SUBSECOND STAT TIME ACCESS
2019
2020Both C<aio_stat>/C<aio_lstat> and perl's C<stat>/C<lstat> functions can
2021generally find access/modification and change times with subsecond time
2022accuracy of the system supports it, but perl's built-in functions only
2023return the integer part.
2024
2025The following functions return the timestamps of the most recent
2026stat with subsecond precision on most systems and work both after
2027C<aio_stat>/C<aio_lstat> and perl's C<stat>/C<lstat> calls. Their return
2028value is only meaningful after a successful C<stat>/C<lstat> call, or
2029during/after a successful C<aio_stat>/C<aio_lstat> callback.
2030
2031This is similar to the L<Time::HiRes> C<stat> functions, but can return
2032full resolution without rounding and work with standard perl C<stat>,
2033alleviating the need to call the special C<Time::HiRes> functions, which
2034do not act like their perl counterparts.
2035
2036On operating systems or file systems where subsecond time resolution is
2037not supported or could not be detected, a fractional part of C<0> is
2038returned, so it is always safe to call these functions.
2039
2040=over 4
2041
2042=item $seconds = IO::AIO::st_atime, IO::AIO::st_mtime, IO::AIO::st_ctime
2043
2044Return the access, modication or change time, respectively, including
2045fractional part. Due to the limited precision of floating point, the
2046accuracy on most platforms is only a bit better than milliseconds for
2047times around now - see the I<nsec> function family, below, for full
2048accuracy.
2049
2050=item ($atime, $mtime, $ctime, ...) = IO::AIO::st_xtime
2051
2052Returns access, modification and change time all in one go, and maybe more
2053times in the future version.
2054
2055=item $nanoseconds = IO::AIO::st_atimensec, IO::AIO::st_mtimensec, IO::AIO::st_ctimensec
2056
2057Return the fractional access, modifcation or change time, in nanoseconds,
2058as an integer in the range C<0> to C<999999999>.
2059
2060=item ($atime, $mtime, $ctime, ...) = IO::AIO::st_xtimensec
2061
2062Like the functions above, but returns all three times in one go (and maybe
2063more in future versions).
2064
2065=back
2066
2067Example: print the high resolution modification time of F</etc>, using
2068C<stat>, and C<IO::AIO::aio_stat>.
2069
2070 if (stat "/etc") {
2071 printf "stat(/etc) mtime: %f\n", IO::AIO::st_mtime;
2072 }
2073
2074 IO::AIO::aio_stat "/etc", sub {
2075 $_[0]
2076 and return;
2077
2078 printf "aio_stat(/etc) mtime: %d.%09d\n", (stat _)[9], IO::AIO::st_mtimensec;
2079 };
2080
2081 IO::AIO::flush;
2082
2083Output of the awbove on my system, showing reduced and full accuracy:
2084
2085 stat(/etc) mtime: 1534043702.020808
2086 aio_stat(/etc) mtime: 1534043702.020807792
2087
2060=head3 MISCELLANEOUS FUNCTIONS 2088=head3 MISCELLANEOUS FUNCTIONS
2061 2089
2062IO::AIO implements some functions that are useful when you want to use 2090IO::AIO implements some functions that are useful when you want to use
2063some "Advanced I/O" function not available to in Perl, without going the 2091some "Advanced I/O" function not available to in Perl, without going the
2064"Asynchronous I/O" route. Many of these have an asynchronous C<aio_*> 2092"Asynchronous I/O" route. Many of these have an asynchronous C<aio_*>
2065counterpart. 2093counterpart.
2066 2094
2067=over 4 2095=over 4
2096
2097=item $numfd = IO::AIO::get_fdlimit
2098
2099This function is I<EXPERIMENTAL> and subject to change.
2100
2101Tries to find the current file descriptor limit and returns it, or
2102C<undef> and sets C<$!> in case of an error. The limit is one larger than
2103the highest valid file descriptor number.
2104
2105=item IO::AIO::min_fdlimit [$numfd]
2106
2107This function is I<EXPERIMENTAL> and subject to change.
2108
2109Try to increase the current file descriptor limit(s) to at least C<$numfd>
2110by changing the soft or hard file descriptor resource limit. If C<$numfd>
2111is missing, it will try to set a very high limit, although this is not
2112recommended when you know the actual minimum that you require.
2113
2114If the limit cannot be raised enough, the function makes a best-effort
2115attempt to increase the limit as much as possible, using various
2116tricks, while still failing. You can query the resulting limit using
2117C<IO::AIO::get_fdlimit>.
2118
2119If an error occurs, returns C<undef> and sets C<$!>, otherwise returns
2120true.
2068 2121
2069=item IO::AIO::sendfile $ofh, $ifh, $offset, $count 2122=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
2070 2123
2071Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>, 2124Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
2072but is blocking (this makes most sense if you know the input data is 2125but is blocking (this makes most sense if you know the input data is
2179 2232
2180=item IO::AIO::munmap $scalar 2233=item IO::AIO::munmap $scalar
2181 2234
2182Removes a previous mmap and undefines the C<$scalar>. 2235Removes a previous mmap and undefines the C<$scalar>.
2183 2236
2237=item IO::AIO::mremap $scalar, $new_length, $flags = MREMAP_MAYMOVE[, $new_address = 0]
2238
2239Calls the Linux-specific mremap(2) system call. The C<$scalar> must have
2240been mapped by C<IO::AIO::mmap>, and C<$flags> must currently either be
2241C<0> or C<IO::AIO::MREMAP_MAYMOVE>.
2242
2243Returns true if successful, and false otherwise. If the underlying mmapped
2244region has changed address, then the true value has the numerical value
2245C<1>, otherwise it has the numerical value C<0>:
2246
2247 my $success = IO::AIO::mremap $mmapped, 8192, IO::AIO::MREMAP_MAYMOVE
2248 or die "mremap: $!";
2249
2250 if ($success*1) {
2251 warn "scalar has chanegd address in memory\n";
2252 }
2253
2254C<IO::AIO::MREMAP_FIXED> and the C<$new_address> argument are currently
2255implemented, but not supported and might go away in a future version.
2256
2257On systems where this call is not supported or is not emulated, this call
2258returns falls and sets C<$!> to C<ENOSYS>.
2259
2184=item IO::AIO::munlock $scalar, $offset = 0, $length = undef 2260=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
2185 2261
2186Calls the C<munlock> function, undoing the effects of a previous 2262Calls the C<munlock> function, undoing the effects of a previous
2187C<aio_mlock> call (see its description for details). 2263C<aio_mlock> call (see its description for details).
2188 2264
2237C<$flags> is non-zero, fails with C<ENOSYS>. 2313C<$flags> is non-zero, fails with C<ENOSYS>.
2238 2314
2239Please refer to L<pipe2(2)> for more info on the C<$flags>, but at the 2315Please refer to L<pipe2(2)> for more info on the C<$flags>, but at the
2240time of this writing, C<IO::AIO::O_CLOEXEC>, C<IO::AIO::O_NONBLOCK> and 2316time of this writing, C<IO::AIO::O_CLOEXEC>, C<IO::AIO::O_NONBLOCK> and
2241C<IO::AIO::O_DIRECT> (Linux 3.4, for packet-based pipes) were supported. 2317C<IO::AIO::O_DIRECT> (Linux 3.4, for packet-based pipes) were supported.
2318
2319Example: create a pipe race-free w.r.t. threads and fork:
2320
2321 my ($rfh, $wfh) = IO::AIO::pipe2 IO::AIO::O_CLOEXEC
2322 or die "pipe2: $!\n";
2323
2324=item $fh = IO::AIO::eventfd [$initval, [$flags]]
2325
2326This is a direct interface to the Linux L<eventfd(2)> system call. The
2327(unhelpful) defaults for C<$initval> and C<$flags> are C<0> for both.
2328
2329On success, the new eventfd filehandle is returned, otherwise returns
2330C<undef>. If the eventfd syscall is missing, fails with C<ENOSYS>.
2331
2332Please refer to L<eventfd(2)> for more info on this call.
2333
2334The following symbol flag values are available: C<IO::AIO::EFD_CLOEXEC>,
2335C<IO::AIO::EFD_NONBLOCK> and C<IO::AIO::EFD_SEMAPHORE> (Linux 2.6.30).
2336
2337Example: create a new eventfd filehandle:
2338
2339 $fh = IO::AIO::eventfd 0, IO::AIO::O_CLOEXEC
2340 or die "eventfd: $!\n";
2341
2342=item $fh = IO::AIO::timerfd_create $clockid[, $flags]
2343
2344This is a direct interface to the Linux L<timerfd_create(2)> system call. The
2345(unhelpful) default for C<$flags> is C<0>.
2346
2347On success, the new timerfd filehandle is returned, otherwise returns
2348C<undef>. If the eventfd syscall is missing, fails with C<ENOSYS>.
2349
2350Please refer to L<timerfd_create(2)> for more info on this call.
2351
2352The following C<$clockid> values are
2353available: C<IO::AIO::CLOCK_REALTIME>, C<IO::AIO::CLOCK_MONOTONIC>
2354C<IO::AIO::CLOCK_CLOCK_BOOTTIME> (Linux 3.15)
2355C<IO::AIO::CLOCK_CLOCK_REALTIME_ALARM> (Linux 3.11) and
2356C<IO::AIO::CLOCK_CLOCK_BOOTTIME_ALARM> (Linux 3.11).
2357
2358The following C<$flags> values are available (Linux
23592.6.27): C<IO::AIO::TFD_NONBLOCK> and C<IO::AIO::TFD_CLOEXEC>.
2360
2361Example: create a new timerfd and set it to one-second repeated alarms,
2362then wait for two alarms:
2363
2364 my $fh = IO::AIO::timerfd_create IO::AIO::CLOCK_BOOTTIME, IO::AIO::TFD_CLOEXEC
2365 or die "timerfd_create: $!\n";
2366
2367 defined IO::AIO::timerfd_settime $fh, 0, 1, 1
2368 or die "timerfd_settime: $!\n";
2369
2370 for (1..2) {
2371 8 == sysread $fh, my $buf, 8
2372 or die "timerfd read failure\n";
2373
2374 printf "number of expirations (likely 1): %d\n",
2375 unpack "Q", $buf;
2376 }
2377
2378=item ($cur_interval, $cur_value) = IO::AIO::timerfd_settime $fh, $flags, $new_interval, $nbw_value
2379
2380This is a direct interface to the Linux L<timerfd_settime(2)> system
2381call. Please refer to its manpage for more info on this call.
2382
2383The new itimerspec is specified using two (possibly fractional) second
2384values, C<$new_interval> and C<$new_value>).
2385
2386On success, the current interval and value are returned (as per
2387C<timerfd_gettime>). On failure, the empty list is returned.
2388
2389The following C<$flags> values are
2390available: C<IO::AIO::TFD_TIMER_ABSTIME> and
2391C<IO::AIO::TFD_TIMER_CANCEL_ON_SET>.
2392
2393See C<IO::AIO::timerfd_create> for a full example.
2394
2395=item ($cur_interval, $cur_value) = IO::AIO::timerfd_gettime $fh
2396
2397This is a direct interface to the Linux L<timerfd_gettime(2)> system
2398call. Please refer to its manpage for more info on this call.
2399
2400On success, returns the current values of interval and value for the given
2401timerfd (as potentially fractional second values). On failure, the empty
2402list is returned.
2242 2403
2243=back 2404=back
2244 2405
2245=cut 2406=cut
2246 2407
2312the process will result in undefined behaviour. Calling it at any time 2473the process will result in undefined behaviour. Calling it at any time
2313will also result in any undefined (by POSIX) behaviour. 2474will also result in any undefined (by POSIX) behaviour.
2314 2475
2315=back 2476=back
2316 2477
2478=head2 LINUX-SPECIFIC CALLS
2479
2480When a call is documented as "linux-specific" then this means it
2481originated on GNU/Linux. C<IO::AIO> will usually try to autodetect the
2482availability and compatibility of such calls regardless of the platform
2483it is compiled on, so platforms such as FreeBSD which often implement
2484these calls will work. When in doubt, call them and see if they fail wth
2485C<ENOSYS>.
2486
2317=head2 MEMORY USAGE 2487=head2 MEMORY USAGE
2318 2488
2319Per-request usage: 2489Per-request usage:
2320 2490
2321Each aio request uses - depending on your architecture - around 100-200 2491Each aio request uses - depending on your architecture - around 100-200
2333temporary buffers, and each thread requires a stack and other data 2503temporary buffers, and each thread requires a stack and other data
2334structures (usually around 16k-128k, depending on the OS). 2504structures (usually around 16k-128k, depending on the OS).
2335 2505
2336=head1 KNOWN BUGS 2506=head1 KNOWN BUGS
2337 2507
2338Known bugs will be fixed in the next release. 2508Known bugs will be fixed in the next release :)
2509
2510=head1 KNOWN ISSUES
2511
2512Calls that try to "import" foreign memory areas (such as C<IO::AIO::mmap>
2513or C<IO::AIO::aio_slurp>) do not work with generic lvalues, such as
2514non-created hash slots or other scalars I didn't think of. It's best to
2515avoid such and either use scalar variables or making sure that the scalar
2516exists (e.g. by storing C<undef>) and isn't "funny" (e.g. tied).
2517
2518I am not sure anything can be done about this, so this is considered a
2519known issue, rather than a bug.
2339 2520
2340=head1 SEE ALSO 2521=head1 SEE ALSO
2341 2522
2342L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a 2523L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
2343more natural syntax. 2524more natural syntax.

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