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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.292 by root, Tue Aug 14 09:29:50 2018 UTC vs.
Revision 1.315 by root, Mon Sep 5 00:03:32 2022 UTC

171use common::sense; 171use common::sense;
172 172
173use base 'Exporter'; 173use base 'Exporter';
174 174
175BEGIN { 175BEGIN {
176 our $VERSION = 4.53; 176 our $VERSION = 4.77;
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
192 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush 192 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
193 min_parallel max_parallel max_idle idle_timeout 193 min_parallel max_parallel max_idle idle_timeout
194 nreqs nready npending nthreads 194 nreqs nready npending nthreads
195 max_poll_time max_poll_reqs 195 max_poll_time max_poll_reqs
196 sendfile fadvise madvise 196 sendfile fadvise madvise
197 mmap munmap mremap munlock munlockall); 197 mmap munmap mremap munlock munlockall
198
199 accept4 tee splice pipe2 pipesize
200 fexecve memfd_create eventfd
201 timerfd_create timerfd_settime timerfd_gettime
202 pidfd_open pidfd_send_signal pidfd_getfd);
198 203
199 push @AIO_REQ, qw(aio_busy); # not exported 204 push @AIO_REQ, qw(aio_busy); # not exported
200 205
201 @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; 206 @IO::AIO::GRP::ISA = 'IO::AIO::REQ';
202 207
278 IO::AIO::idle_timeout $seconds 283 IO::AIO::idle_timeout $seconds
279 IO::AIO::max_outstanding $maxreqs 284 IO::AIO::max_outstanding $maxreqs
280 IO::AIO::nreqs 285 IO::AIO::nreqs
281 IO::AIO::nready 286 IO::AIO::nready
282 IO::AIO::npending 287 IO::AIO::npending
288 IO::AIO::reinit
289
283 $nfd = IO::AIO::get_fdlimit [EXPERIMENTAL] 290 $nfd = IO::AIO::get_fdlimit
284 IO::AIO::min_fdlimit $nfd [EXPERIMENTAL] 291 IO::AIO::min_fdlimit $nfd
285 292
286 IO::AIO::sendfile $ofh, $ifh, $offset, $count 293 IO::AIO::sendfile $ofh, $ifh, $offset, $count
287 IO::AIO::fadvise $fh, $offset, $len, $advice 294 IO::AIO::fadvise $fh, $offset, $len, $advice
295 IO::AIO::fexecve $fh, $argv, $envp
296
288 IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]] 297 IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
289 IO::AIO::munmap $scalar 298 IO::AIO::munmap $scalar
290 IO::AIO::mremap $scalar, $new_length, $flags[, $new_address] 299 IO::AIO::mremap $scalar, $new_length, $flags[, $new_address]
291 IO::AIO::madvise $scalar, $offset, $length, $advice 300 IO::AIO::madvise $scalar, $offset, $length, $advice
292 IO::AIO::mprotect $scalar, $offset, $length, $protect 301 IO::AIO::mprotect $scalar, $offset, $length, $protect
293 IO::AIO::munlock $scalar, $offset = 0, $length = undef 302 IO::AIO::munlock $scalar, $offset = 0, $length = undef
294 IO::AIO::munlockall 303 IO::AIO::munlockall
304
305 # stat extensions
306 $counter = IO::AIO::st_gen
307 $seconds = IO::AIO::st_atime, IO::AIO::st_mtime, IO::AIO::st_ctime, IO::AIO::st_btime
308 ($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtime
309 $nanoseconds = IO::AIO::st_atimensec, IO::AIO::st_mtimensec, IO::AIO::st_ctimensec, IO::AIO::st_btimensec
310 $seconds = IO::AIO::st_btimesec
311 ($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtimensec
312
313 # very much unportable syscalls
314 IO::AIO::accept4 $r_fh, $sockaddr, $sockaddr_len, $flags
315 IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
316 IO::AIO::tee $r_fh, $w_fh, $length, $flags
317
318 $actual_size = IO::AIO::pipesize $r_fh[, $new_size]
319 ($rfh, $wfh) = IO::AIO::pipe2 [$flags]
320
321 $fh = IO::AIO::eventfd [$initval, [$flags]]
322 $fh = IO::AIO::memfd_create $pathname[, $flags]
323
324 $fh = IO::AIO::timerfd_create $clockid[, $flags]
325 ($cur_interval, $cur_value) = IO::AIO::timerfd_settime $fh, $flags, $new_interval, $nbw_value
326 ($cur_interval, $cur_value) = IO::AIO::timerfd_gettime $fh
327
328 $fh = IO::AIO::pidfd_open $pid[, $flags]
329 $status = IO::AIO::pidfd_send_signal $pidfh, $signal[, $siginfo[, $flags]]
330 $fh = IO::AIO::pidfd_getfd $pidfh, $targetfd[, $flags]
295 331
296=head2 API NOTES 332=head2 API NOTES
297 333
298All the C<aio_*> calls are more or less thin wrappers around the syscall 334All the C<aio_*> calls are more or less thin wrappers around the syscall
299with the same name (sans C<aio_>). The arguments are similar or identical, 335with the same name (sans C<aio_>). The arguments are similar or identical,
541 577
542=item aio_stat $fh_or_path, $callback->($status) 578=item aio_stat $fh_or_path, $callback->($status)
543 579
544=item aio_lstat $fh, $callback->($status) 580=item aio_lstat $fh, $callback->($status)
545 581
546Works like perl's C<stat> or C<lstat> in void context. The callback will 582Works almost exactly like perl's C<stat> or C<lstat> in void context. The
547be called after the stat and the results will be available using C<stat _> 583callback will be called after the stat and the results will be available
548or C<-s _> etc... 584using C<stat _> or C<-s _> and other tests (with the exception of C<-B>
585and C<-T>).
549 586
550The pathname passed to C<aio_stat> must be absolute. See API NOTES, above, 587The pathname passed to C<aio_stat> must be absolute. See API NOTES, above,
551for an explanation. 588for an explanation.
552 589
553Currently, the stats are always 64-bit-stats, i.e. instead of returning an 590Currently, the stats are always 64-bit-stats, i.e. instead of returning an
622 659
623Works like perl's C<utime> function (including the special case of $atime 660Works like perl's C<utime> function (including the special case of $atime
624and $mtime being undef). Fractional times are supported if the underlying 661and $mtime being undef). Fractional times are supported if the underlying
625syscalls support them. 662syscalls support them.
626 663
627When called with a pathname, uses utimes(2) if available, otherwise 664When called with a pathname, uses utimensat(2) or utimes(2) if available,
628utime(2). If called on a file descriptor, uses futimes(2) if available, 665otherwise utime(2). If called on a file descriptor, uses futimens(2)
629otherwise returns ENOSYS, so this is not portable. 666or futimes(2) if available, otherwise returns ENOSYS, so this is not
667portable.
630 668
631Examples: 669Examples:
632 670
633 # set atime and mtime to current time (basically touch(1)): 671 # set atime and mtime to current time (basically touch(1)):
634 aio_utime "path", undef, undef; 672 aio_utime "path", undef, undef;
1107 aioreq_pri $pri; 1145 aioreq_pri $pri;
1108 add $grp aio_stat $wd, sub { 1146 add $grp aio_stat $wd, sub {
1109 return $grp->result () if $_[0]; 1147 return $grp->result () if $_[0];
1110 my $now = time; 1148 my $now = time;
1111 my $hash1 = join ":", (stat _)[0,1,3,7,9]; 1149 my $hash1 = join ":", (stat _)[0,1,3,7,9];
1150 my $rdxflags = READDIR_DIRS_FIRST;
1151
1152 if ((stat _)[3] < 2) {
1153 # at least one non-POSIX filesystem exists
1154 # that returns useful DT_type values: btrfs,
1155 # so optimise for this here by requesting dents
1156 $rdxflags |= READDIR_DENTS;
1157 }
1112 1158
1113 # read the directory entries 1159 # read the directory entries
1114 aioreq_pri $pri; 1160 aioreq_pri $pri;
1115 add $grp aio_readdirx $wd, READDIR_DIRS_FIRST, sub { 1161 add $grp aio_readdirx $wd, $rdxflags, sub {
1116 my $entries = shift 1162 my ($entries, $flags) = @_
1117 or return $grp->result (); 1163 or return $grp->result ();
1164
1165 if ($rdxflags & READDIR_DENTS) {
1166 # if we requested type values, see if we can use them directly.
1167
1168 # if there were any DT_UNKNOWN entries then we assume we
1169 # don't know. alternatively, we could assume that if we get
1170 # one DT_DIR, then all directories are indeed marked with
1171 # DT_DIR, but this seems not required for btrfs, and this
1172 # is basically the "btrfs can't get it's act together" code
1173 # branch.
1174 unless ($flags & READDIR_FOUND_UNKNOWN) {
1175 # now we have valid DT_ information for all entries,
1176 # so use it as an optimisation without further stat's.
1177 # they must also all be at the beginning of @$entries
1178 # by now.
1179
1180 my $dirs;
1181
1182 if (@$entries) {
1183 for (0 .. $#$entries) {
1184 if ($entries->[$_][1] != DT_DIR) {
1185 # splice out directories
1186 $dirs = [splice @$entries, 0, $_];
1187 last;
1188 }
1189 }
1190
1191 # if we didn't find any non-dir, then all entries are dirs
1192 unless ($dirs) {
1193 ($dirs, $entries) = ($entries, []);
1194 }
1195 } else {
1196 # directory is empty, so there are no sbdirs
1197 $dirs = [];
1198 }
1199
1200 # either splice'd the directories out or the dir was empty.
1201 # convert dents to filenames
1202 $_ = $_->[0] for @$dirs;
1203 $_ = $_->[0] for @$entries;
1204
1205 return $grp->result ($dirs, $entries);
1206 }
1207
1208 # cannot use, so return to our old ways
1209 # by pretending we only scanned for names.
1210 $_ = $_->[0] for @$entries;
1211 }
1118 1212
1119 # stat the dir another time 1213 # stat the dir another time
1120 aioreq_pri $pri; 1214 aioreq_pri $pri;
1121 add $grp aio_stat $wd, sub { 1215 add $grp aio_stat $wd, sub {
1122 my $hash2 = join ":", (stat _)[0,1,3,7,9]; 1216 my $hash2 = join ":", (stat _)[0,1,3,7,9];
1228So in general, you should only use these calls for things that do 1322So in general, you should only use these calls for things that do
1229(filesystem) I/O, not for things that wait for other events (network, 1323(filesystem) I/O, not for things that wait for other events (network,
1230other processes), although if you are careful and know what you are doing, 1324other processes), although if you are careful and know what you are doing,
1231you still can. 1325you still can.
1232 1326
1233The following constants are available (missing ones are, as usual C<0>): 1327The following constants are available and can be used for normal C<ioctl>
1328and C<fcntl> as well (missing ones are, as usual C<0>):
1234 1329
1235C<F_DUPFD_CLOEXEC>, 1330C<F_DUPFD_CLOEXEC>,
1236 1331
1237C<F_OFD_GETLK>, C<F_OFD_SETLK>, C<F_OFD_GETLKW>, 1332C<F_OFD_GETLK>, C<F_OFD_SETLK>, C<F_OFD_GETLKW>,
1238 1333
1239C<FIFREEZE>, C<FITHAW>, C<FITRIM>, C<FICLONE>, C<FICLONERANGE>, C<FIDEDUPERANGE>. 1334C<FIFREEZE>, C<FITHAW>, C<FITRIM>, C<FICLONE>, C<FICLONERANGE>, C<FIDEDUPERANGE>.
1335
1336C<F_ADD_SEALS>, C<F_GET_SEALS>, C<F_SEAL_SEAL>, C<F_SEAL_SHRINK>, C<F_SEAL_GROW> and
1337C<F_SEAL_WRITE>.
1240 1338
1241C<FS_IOC_GETFLAGS>, C<FS_IOC_SETFLAGS>, C<FS_IOC_GETVERSION>, C<FS_IOC_SETVERSION>, 1339C<FS_IOC_GETFLAGS>, C<FS_IOC_SETFLAGS>, C<FS_IOC_GETVERSION>, C<FS_IOC_SETVERSION>,
1242C<FS_IOC_FIEMAP>. 1340C<FS_IOC_FIEMAP>.
1243 1341
1244C<FS_IOC_FSGETXATTR>, C<FS_IOC_FSSETXATTR>, C<FS_IOC_SET_ENCRYPTION_POLICY>, 1342C<FS_IOC_FSGETXATTR>, C<FS_IOC_FSSETXATTR>, C<FS_IOC_SET_ENCRYPTION_POLICY>,
1383 IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh; 1481 IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
1384 aio_mlock $data; # mlock in background 1482 aio_mlock $data; # mlock in background
1385 1483
1386=item aio_mlockall $flags, $callback->($status) 1484=item aio_mlockall $flags, $callback->($status)
1387 1485
1388Calls the C<mlockall> function with the given C<$flags> (a combination of 1486Calls the C<mlockall> function with the given C<$flags> (a
1389C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>). 1487combination of C<IO::AIO::MCL_CURRENT>, C<IO::AIO::MCL_FUTURE> and
1488C<IO::AIO::MCL_ONFAULT>).
1390 1489
1391On systems that do not implement C<mlockall>, this function returns C<-1> 1490On systems that do not implement C<mlockall>, this function returns C<-1>
1392and sets errno to C<ENOSYS>. 1491and sets errno to C<ENOSYS>. Similarly, flag combinations not supported
1492by the system result in a return value of C<-1> with errno being set to
1493C<EINVAL>.
1393 1494
1394Note that the corresponding C<munlockall> is synchronous and is 1495Note that the corresponding C<munlockall> is synchronous and is
1395documented under L<MISCELLANEOUS FUNCTIONS>. 1496documented under L<MISCELLANEOUS FUNCTIONS>.
1396 1497
1397Example: asynchronously lock all current and future pages into memory. 1498Example: asynchronously lock all current and future pages into memory.
1591C<aio_wd> callback, as future requests using the value will fail in the 1692C<aio_wd> callback, as future requests using the value will fail in the
1592expected way. 1693expected way.
1593 1694
1594=item IO::AIO::CWD 1695=item IO::AIO::CWD
1595 1696
1596This is a compiletime constant (object) that represents the process 1697This is a compile time constant (object) that represents the process
1597current working directory. 1698current working directory.
1598 1699
1599Specifying this object as working directory object for a pathname is as if 1700Specifying this object as working directory object for a pathname is as if
1600the pathname would be specified directly, without a directory object. For 1701the pathname would be specified directly, without a directory object. For
1601example, these calls are functionally identical: 1702example, these calls are functionally identical:
1782The default value for the limit is C<0>, but note that setting a feeder 1883The default value for the limit is C<0>, but note that setting a feeder
1783automatically bumps it up to C<2>. 1884automatically bumps it up to C<2>.
1784 1885
1785=back 1886=back
1786 1887
1888
1787=head2 SUPPORT FUNCTIONS 1889=head2 SUPPORT FUNCTIONS
1788 1890
1789=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION 1891=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
1790 1892
1791=over 4 1893=over 4
1856Strictly equivalent to: 1958Strictly equivalent to:
1857 1959
1858 IO::AIO::poll_wait, IO::AIO::poll_cb 1960 IO::AIO::poll_wait, IO::AIO::poll_cb
1859 while IO::AIO::nreqs; 1961 while IO::AIO::nreqs;
1860 1962
1963This function can be useful at program aborts, to make sure outstanding
1964I/O has been done (C<IO::AIO> uses an C<END> block which already calls
1965this function on normal exits), or when you are merely using C<IO::AIO>
1966for its more advanced functions, rather than for async I/O, e.g.:
1967
1968 my ($dirs, $nondirs);
1969 IO::AIO::aio_scandir "/tmp", 0, sub { ($dirs, $nondirs) = @_ };
1970 IO::AIO::flush;
1971 # $dirs, $nondirs are now set
1972
1861=item IO::AIO::max_poll_reqs $nreqs 1973=item IO::AIO::max_poll_reqs $nreqs
1862 1974
1863=item IO::AIO::max_poll_time $seconds 1975=item IO::AIO::max_poll_time $seconds
1864 1976
1865These set the maximum number of requests (default C<0>, meaning infinity) 1977These set the maximum number of requests (default C<0>, meaning infinity)
1891 poll => 'r', nice => 1, 2003 poll => 'r', nice => 1,
1892 cb => &IO::AIO::poll_cb); 2004 cb => &IO::AIO::poll_cb);
1893 2005
1894=back 2006=back
1895 2007
2008
1896=head3 CONTROLLING THE NUMBER OF THREADS 2009=head3 CONTROLLING THE NUMBER OF THREADS
1897 2010
1898=over 2011=over
1899 2012
1900=item IO::AIO::min_parallel $nthreads 2013=item IO::AIO::min_parallel $nthreads
1961longer exceeded. 2074longer exceeded.
1962 2075
1963In other words, this setting does not enforce a queue limit, but can be 2076In other words, this setting does not enforce a queue limit, but can be
1964used to make poll functions block if the limit is exceeded. 2077used to make poll functions block if the limit is exceeded.
1965 2078
1966This is a very bad function to use in interactive programs because it 2079This is a bad function to use in interactive programs because it blocks,
1967blocks, and a bad way to reduce concurrency because it is inexact: Better 2080and a bad way to reduce concurrency because it is inexact. If you need to
2081issue many requests without being able to call a poll function on demand,
1968use an C<aio_group> together with a feed callback. 2082it is better to use an C<aio_group> together with a feed callback.
1969 2083
1970Its main use is in scripts without an event loop - when you want to stat 2084Its main use is in scripts without an event loop - when you want to stat a
1971a lot of files, you can write something like this: 2085lot of files, you can write something like this:
1972 2086
1973 IO::AIO::max_outstanding 32; 2087 IO::AIO::max_outstanding 32;
1974 2088
1975 for my $path (...) { 2089 for my $path (...) {
1976 aio_stat $path , ...; 2090 aio_stat $path , ...;
1977 IO::AIO::poll_cb; 2091 IO::AIO::poll_cb;
1978 } 2092 }
1979 2093
1980 IO::AIO::flush; 2094 IO::AIO::flush;
1981 2095
1982The call to C<poll_cb> inside the loop will normally return instantly, but 2096The call to C<poll_cb> inside the loop will normally return instantly,
1983as soon as more thna C<32> reqeusts are in-flight, it will block until 2097allowing the loop to progress, but as soon as more than C<32> requests
1984some requests have been handled. This keeps the loop from pushing a large 2098are in-flight, it will block until some requests have been handled. This
1985number of C<aio_stat> requests onto the queue. 2099keeps the loop from pushing a large number of C<aio_stat> requests onto
2100the queue (which, with many paths to stat, can use up a lot of memory).
1986 2101
1987The default value for C<max_outstanding> is very large, so there is no 2102The default value for C<max_outstanding> is very large, so there is no
1988practical limit on the number of outstanding requests. 2103practical limit on the number of outstanding requests.
1989 2104
1990=back 2105=back
1991 2106
2107
1992=head3 STATISTICAL INFORMATION 2108=head3 STATISTICAL INFORMATION
1993 2109
1994=over 2110=over
1995 2111
1996=item IO::AIO::nreqs 2112=item IO::AIO::nreqs
2012 2128
2013Returns the number of requests currently in the pending state (executed, 2129Returns the number of requests currently in the pending state (executed,
2014but not yet processed by poll_cb). 2130but not yet processed by poll_cb).
2015 2131
2016=back 2132=back
2133
2017 2134
2018=head3 SUBSECOND STAT TIME ACCESS 2135=head3 SUBSECOND STAT TIME ACCESS
2019 2136
2020Both C<aio_stat>/C<aio_lstat> and perl's C<stat>/C<lstat> functions can 2137Both 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 2138generally find access/modification and change times with subsecond time
2037not supported or could not be detected, a fractional part of C<0> is 2154not supported or could not be detected, a fractional part of C<0> is
2038returned, so it is always safe to call these functions. 2155returned, so it is always safe to call these functions.
2039 2156
2040=over 4 2157=over 4
2041 2158
2042=item $seconds = IO::AIO::st_atime, IO::AIO::st_mtime, IO::AIO::st_ctime 2159=item $seconds = IO::AIO::st_atime, IO::AIO::st_mtime, IO::AIO::st_ctime, IO::AIO::st_btime
2043 2160
2044Return the access, modication or change time, respectively, including 2161Return the access, modication, change or birth time, respectively,
2045fractional part. Due to the limited precision of floating point, the 2162including fractional part. Due to the limited precision of floating point,
2046accuracy on most platforms is only a bit better than milliseconds for 2163the accuracy on most platforms is only a bit better than milliseconds
2047times around now - see the I<nsec> function family, below, for full 2164for times around now - see the I<nsec> function family, below, for full
2048accuracy. 2165accuracy.
2049 2166
2167File birth time is only available when the OS and perl support it (on
2168FreeBSD and NetBSD at the time of this writing, although support is
2169adaptive, so if your OS/perl gains support, IO::AIO can take advantage of
2170it). On systems where it isn't available, C<0> is currently returned, but
2171this might change to C<undef> in a future version.
2172
2050=item ($atime, $mtime, $ctime, ...) = IO::AIO::st_xtime 2173=item ($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtime
2051 2174
2052Returns access, modification and change time all in one go, and maybe more 2175Returns access, modification, change and birth time all in one go, and
2053times in the future version. 2176maybe more times in the future version.
2054 2177
2055=item $nanoseconds = IO::AIO::st_atimensec, IO::AIO::st_mtimensec, IO::AIO::st_ctimensec 2178=item $nanoseconds = IO::AIO::st_atimensec, IO::AIO::st_mtimensec, IO::AIO::st_ctimensec, IO::AIO::st_btimensec
2056 2179
2057Return the fractional access, modifcation or change time, in nanoseconds, 2180Return the fractional access, modifcation, change or birth time, in nanoseconds,
2058as an integer in the range C<0> to C<999999999>. 2181as an integer in the range C<0> to C<999999999>.
2059 2182
2183Note that no accessors are provided for access, modification and
2184change times - you need to get those from C<stat _> if required (C<int
2185IO::AIO::st_atime> and so on will I<not> generally give you the correct
2186value).
2187
2188=item $seconds = IO::AIO::st_btimesec
2189
2190The (integral) seconds part of the file birth time, if available.
2191
2060=item ($atime, $mtime, $ctime, ...) = IO::AIO::st_xtimensec 2192=item ($atime, $mtime, $ctime, $btime, ...) = IO::AIO::st_xtimensec
2061 2193
2062Like the functions above, but returns all three times in one go (and maybe 2194Like the functions above, but returns all four times in one go (and maybe
2063more in future versions). 2195more in future versions).
2196
2197=item $counter = IO::AIO::st_gen
2198
2199Returns the generation counter (in practice this is just a random number)
2200of the file. This is only available on platforms which have this member in
2201their C<struct stat> (most BSDs at the time of this writing) and generally
2202only to the root usert. If unsupported, C<0> is returned, but this might
2203change to C<undef> in a future version.
2064 2204
2065=back 2205=back
2066 2206
2067Example: print the high resolution modification time of F</etc>, using 2207Example: print the high resolution modification time of F</etc>, using
2068C<stat>, and C<IO::AIO::aio_stat>. 2208C<stat>, and C<IO::AIO::aio_stat>.
2082 2222
2083Output of the awbove on my system, showing reduced and full accuracy: 2223Output of the awbove on my system, showing reduced and full accuracy:
2084 2224
2085 stat(/etc) mtime: 1534043702.020808 2225 stat(/etc) mtime: 1534043702.020808
2086 aio_stat(/etc) mtime: 1534043702.020807792 2226 aio_stat(/etc) mtime: 1534043702.020807792
2227
2087 2228
2088=head3 MISCELLANEOUS FUNCTIONS 2229=head3 MISCELLANEOUS FUNCTIONS
2089 2230
2090IO::AIO implements some functions that are useful when you want to use 2231IO::AIO implements some functions that are useful when you want to use
2091some "Advanced I/O" function not available to in Perl, without going the 2232some "Advanced I/O" function not available to in Perl, without going the
2092"Asynchronous I/O" route. Many of these have an asynchronous C<aio_*> 2233"Asynchronous I/O" route. Many of these have an asynchronous C<aio_*>
2093counterpart. 2234counterpart.
2094 2235
2095=over 4 2236=over 4
2096 2237
2238=item $retval = IO::AIO::fexecve $fh, $argv, $envp
2239
2240A more-or-less direct equivalent to the POSIX C<fexecve> functions, which
2241allows you to specify the program to be executed via a file descriptor (or
2242handle). Returns C<-1> and sets errno to C<ENOSYS> if not available.
2243
2097=item $numfd = IO::AIO::get_fdlimit 2244=item $numfd = IO::AIO::get_fdlimit
2098
2099This function is I<EXPERIMENTAL> and subject to change.
2100 2245
2101Tries to find the current file descriptor limit and returns it, or 2246Tries to find the current file descriptor limit and returns it, or
2102C<undef> and sets C<$!> in case of an error. The limit is one larger than 2247C<undef> and sets C<$!> in case of an error. The limit is one larger than
2103the highest valid file descriptor number. 2248the highest valid file descriptor number.
2104 2249
2105=item IO::AIO::min_fdlimit [$numfd] 2250=item IO::AIO::min_fdlimit [$numfd]
2106
2107This function is I<EXPERIMENTAL> and subject to change.
2108 2251
2109Try to increase the current file descriptor limit(s) to at least C<$numfd> 2252Try 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> 2253by changing the soft or hard file descriptor resource limit. If C<$numfd>
2111is missing, it will try to set a very high limit, although this is not 2254is missing, it will try to set a very high limit, although this is not
2112recommended when you know the actual minimum that you require. 2255recommended when you know the actual minimum that you require.
2207C<IO::AIO::MAP_POPULATE>, 2350C<IO::AIO::MAP_POPULATE>,
2208C<IO::AIO::MAP_NONBLOCK>, 2351C<IO::AIO::MAP_NONBLOCK>,
2209C<IO::AIO::MAP_FIXED>, 2352C<IO::AIO::MAP_FIXED>,
2210C<IO::AIO::MAP_GROWSDOWN>, 2353C<IO::AIO::MAP_GROWSDOWN>,
2211C<IO::AIO::MAP_32BIT>, 2354C<IO::AIO::MAP_32BIT>,
2212C<IO::AIO::MAP_HUGETLB> or 2355C<IO::AIO::MAP_HUGETLB>,
2213C<IO::AIO::MAP_STACK>. 2356C<IO::AIO::MAP_STACK>,
2357C<IO::AIO::MAP_FIXED_NOREPLACE>,
2358C<IO::AIO::MAP_SHARED_VALIDATE>,
2359C<IO::AIO::MAP_SYNC> or
2360C<IO::AIO::MAP_UNINITIALIZED>.
2214 2361
2215If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed. 2362If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
2216 2363
2217C<$offset> is the offset from the start of the file - it generally must be 2364C<$offset> is the offset from the start of the file - it generally must be
2218a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>. 2365a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
2255implemented, but not supported and might go away in a future version. 2402implemented, but not supported and might go away in a future version.
2256 2403
2257On systems where this call is not supported or is not emulated, this call 2404On systems where this call is not supported or is not emulated, this call
2258returns falls and sets C<$!> to C<ENOSYS>. 2405returns falls and sets C<$!> to C<ENOSYS>.
2259 2406
2407=item IO::AIO::mlockall $flags
2408
2409Calls the C<eio_mlockall_sync> function, which is like C<aio_mlockall>,
2410but is blocking.
2411
2260=item IO::AIO::munlock $scalar, $offset = 0, $length = undef 2412=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
2261 2413
2262Calls the C<munlock> function, undoing the effects of a previous 2414Calls the C<munlock> function, undoing the effects of a previous
2263C<aio_mlock> call (see its description for details). 2415C<aio_mlock> call (see its description for details).
2264 2416
2266 2418
2267Calls the C<munlockall> function. 2419Calls the C<munlockall> function.
2268 2420
2269On systems that do not implement C<munlockall>, this function returns 2421On systems that do not implement C<munlockall>, this function returns
2270ENOSYS, otherwise the return value of C<munlockall>. 2422ENOSYS, otherwise the return value of C<munlockall>.
2423
2424=item $fh = IO::AIO::accept4 $r_fh, $sockaddr, $sockaddr_maxlen, $flags
2425
2426Uses the GNU/Linux C<accept4(2)> syscall, if available, to accept a socket
2427and return the new file handle on success, or sets C<$!> and returns
2428C<undef> on error.
2429
2430The remote name of the new socket will be stored in C<$sockaddr>, which
2431will be extended to allow for at least C<$sockaddr_maxlen> octets. If the
2432socket name does not fit into C<$sockaddr_maxlen> octets, this is signaled
2433by returning a longer string in C<$sockaddr>, which might or might not be
2434truncated.
2435
2436To accept name-less sockets, use C<undef> for C<$sockaddr> and C<0> for
2437C<$sockaddr_maxlen>.
2438
2439The main reasons to use this syscall rather than portable C<accept(2)>
2440are that you can specify C<SOCK_NONBLOCK> and/or C<SOCK_CLOEXEC>
2441flags and you can accept name-less sockets by specifying C<0> for
2442C<$sockaddr_maxlen>, which is sadly not possible with perl's interface to
2443C<accept>.
2271 2444
2272=item IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags 2445=item IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
2273 2446
2274Calls the GNU/Linux C<splice(2)> syscall, if available. If C<$r_off> or 2447Calls the GNU/Linux C<splice(2)> syscall, if available. If C<$r_off> or
2275C<$w_off> are C<undef>, then C<NULL> is passed for these, otherwise they 2448C<$w_off> are C<undef>, then C<NULL> is passed for these, otherwise they
2319Example: create a pipe race-free w.r.t. threads and fork: 2492Example: create a pipe race-free w.r.t. threads and fork:
2320 2493
2321 my ($rfh, $wfh) = IO::AIO::pipe2 IO::AIO::O_CLOEXEC 2494 my ($rfh, $wfh) = IO::AIO::pipe2 IO::AIO::O_CLOEXEC
2322 or die "pipe2: $!\n"; 2495 or die "pipe2: $!\n";
2323 2496
2497=item $fh = IO::AIO::memfd_create $pathname[, $flags]
2498
2499This is a direct interface to the Linux L<memfd_create(2)> system
2500call. The (unhelpful) default for C<$flags> is C<0>, but your default
2501should be C<IO::AIO::MFD_CLOEXEC>.
2502
2503On success, the new memfd filehandle is returned, otherwise returns
2504C<undef>. If the memfd_create syscall is missing, fails with C<ENOSYS>.
2505
2506Please refer to L<memfd_create(2)> for more info on this call.
2507
2508The following C<$flags> values are available: C<IO::AIO::MFD_CLOEXEC>,
2509C<IO::AIO::MFD_ALLOW_SEALING>, C<IO::AIO::MFD_HUGETLB>,
2510C<IO::AIO::MFD_HUGETLB_2MB> and C<IO::AIO::MFD_HUGETLB_1GB>.
2511
2512Example: create a new memfd.
2513
2514 my $fh = IO::AIO::memfd_create "somenameforprocfd", IO::AIO::MFD_CLOEXEC
2515 or die "memfd_create: $!\n";
2516
2517=item $fh = IO::AIO::pidfd_open $pid[, $flags]
2518
2519This is an interface to the Linux L<pidfd_open(2)> system call. The
2520default for C<$flags> is C<0>.
2521
2522On success, a new pidfd filehandle is returned (that is already set to
2523close-on-exec), otherwise returns C<undef>. If the syscall is missing,
2524fails with C<ENOSYS>.
2525
2526Example: open pid 6341 as pidfd.
2527
2528 my $fh = IO::AIO::pidfd_open 6341
2529 or die "pidfd_open: $!\n";
2530
2531=item $status = IO::AIO::pidfd_send_signal $pidfh, $signal[, $siginfo[, $flags]]
2532
2533This is an interface to the Linux L<pidfd_send_signal> system call. The
2534default for C<$siginfo> is C<undef> and the default for C<$flags> is C<0>.
2535
2536Returns the system call status. If the syscall is missing, fails with
2537C<ENOSYS>.
2538
2539When specified, C<$siginfo> must be a reference to a hash with one or more
2540of the following members:
2541
2542=over
2543
2544=item code - the C<si_code> member
2545
2546=item pid - the C<si_pid> member
2547
2548=item uid - the C<si_uid> member
2549
2550=item value_int - the C<si_value.sival_int> member
2551
2552=item value_ptr - the C<si_value.sival_ptr> member, specified as an integer
2553
2554=back
2555
2556Example: send a SIGKILL to the specified process.
2557
2558 my $status = IO::AIO::pidfd_send_signal $pidfh, 9, undef
2559 and die "pidfd_send_signal: $!\n";
2560
2561Example: send a SIGKILL to the specified process with extra data.
2562
2563 my $status = IO::AIO::pidfd_send_signal $pidfh, 9, { code => -1, value_int => 7 }
2564 and die "pidfd_send_signal: $!\n";
2565
2566=item $fh = IO::AIO::pidfd_getfd $pidfh, $targetfd[, $flags]
2567
2568This is an interface to the Linux L<pidfd_getfd> system call. The default
2569for C<$flags> is C<0>.
2570
2571On success, returns a dup'ed copy of the target file descriptor (specified
2572as an integer) returned (that is already set to close-on-exec), otherwise
2573returns C<undef>. If the syscall is missing, fails with C<ENOSYS>.
2574
2575Example: get a copy of standard error of another process and print soemthing to it.
2576
2577 my $errfh = IO::AIO::pidfd_getfd $pidfh, 2
2578 or die "pidfd_getfd: $!\n";
2579 print $errfh "stderr\n";
2580
2324=item $fh = IO::AIO::eventfd [$initval, [$flags]] 2581=item $fh = IO::AIO::eventfd [$initval, [$flags]]
2325 2582
2326This is a direct interface to the Linux L<eventfd(2)> system call. The 2583This is a direct interface to the Linux L<eventfd(2)> system call. The
2327(unhelpful) defaults for C<$initval> and C<$flags> are C<0> for both. 2584(unhelpful) defaults for C<$initval> and C<$flags> are C<0> for both.
2328 2585
2334The following symbol flag values are available: C<IO::AIO::EFD_CLOEXEC>, 2591The 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). 2592C<IO::AIO::EFD_NONBLOCK> and C<IO::AIO::EFD_SEMAPHORE> (Linux 2.6.30).
2336 2593
2337Example: create a new eventfd filehandle: 2594Example: create a new eventfd filehandle:
2338 2595
2339 $fh = IO::AIO::eventfd 0, IO::AIO::O_CLOEXEC 2596 $fh = IO::AIO::eventfd 0, IO::AIO::EFD_CLOEXEC
2340 or die "eventfd: $!\n"; 2597 or die "eventfd: $!\n";
2341 2598
2342=item $fh = IO::AIO::timerfd_create $clockid[, $flags] 2599=item $fh = IO::AIO::timerfd_create $clockid[, $flags]
2343 2600
2344This is a direct interface to the Linux L<timerfd_create(2)> system call. The 2601This is a direct interface to the Linux L<timerfd_create(2)> system
2345(unhelpful) default for C<$flags> is C<0>. 2602call. The (unhelpful) default for C<$flags> is C<0>, but your default
2603should be C<IO::AIO::TFD_CLOEXEC>.
2346 2604
2347On success, the new timerfd filehandle is returned, otherwise returns 2605On success, the new timerfd filehandle is returned, otherwise returns
2348C<undef>. If the eventfd syscall is missing, fails with C<ENOSYS>. 2606C<undef>. If the timerfd_create syscall is missing, fails with C<ENOSYS>.
2349 2607
2350Please refer to L<timerfd_create(2)> for more info on this call. 2608Please refer to L<timerfd_create(2)> for more info on this call.
2351 2609
2352The following C<$clockid> values are 2610The following C<$clockid> values are
2353available: C<IO::AIO::CLOCK_REALTIME>, C<IO::AIO::CLOCK_MONOTONIC> 2611available: C<IO::AIO::CLOCK_REALTIME>, C<IO::AIO::CLOCK_MONOTONIC>
2519known issue, rather than a bug. 2777known issue, rather than a bug.
2520 2778
2521=head1 SEE ALSO 2779=head1 SEE ALSO
2522 2780
2523L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a 2781L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
2524more natural syntax. 2782more natural syntax and L<IO::FDPass> for file descriptor passing.
2525 2783
2526=head1 AUTHOR 2784=head1 AUTHOR
2527 2785
2528 Marc Lehmann <schmorp@schmorp.de> 2786 Marc Lehmann <schmorp@schmorp.de>
2529 http://home.schmorp.de/ 2787 http://home.schmorp.de/

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