Provided by: libposix-2008-perl_0.16-1_amd64 
NAME
POSIX::2008 - Perl interface to POSIX.1-2008
SYNOPSIS
use Fcntl;
use POSIX::2008 qw(openat pwrite);
sysopen my $dh, '/tmp', O_RDONLY|O_DIRECTORY|O_NOFOLLOW or die 'Dafuq?';
my $fh = openat($dh, 'foobar', O_RDWR|O_CREAT);
pwrite($fh, 'fuckyounsa', 10, 0);
DESCRIPTION
POSIX::2008 contains many of the interfaces specified by POSIX.1-2008
<http://pubs.opengroup.org/onlinepubs/9699919799/> that the core POSIX module withholds, implements in
Perl or fucked up.
This module is provided "as is" unless someone volunteers to maintain it.
INCOMPATIBLE PARAMETER CHANGE
Since version 0.13, the parameter order of pread/pwrite is (count, offset) as with the actual system
calls instead of (offset, count). Good luck.
FILE DESCRIPTORS AND HANDLES
Since version 0.05, all I/O functions that take numeric file descriptors also accept Perl file or
directory handles. "openat()" even returns a handle if you passed it one.
SYSTEM CALL RETURN VALUES
A system call return value of -1 meaning "error" is mapped to undef.
A system call return value of 0 meaning "success" is mapped to "0 but true".
For system calls where 0 does not just mean "success", 0 is returned unchanged. These are "open()",
"read()", "write()", "readv()", "writev()", "pread()", "pwrite()", "preadv()", "pwritev()". "openat()"
gets a special treatment in this module, see below.
FUNCTIONS
a64l
l = a64l(s);
abort
abort();
abs ui = abs(i);
access
ret = access(path, mode);
acos
y = acos(x);
acosh
y = acosh(x);
alarm
remaining_sec = alarm(sec);
asin
y = asin(x);
asinh
y = asinh(x);
atan2
z = atan2(y, x);
atan
y = atan(x);
atanh
y = atanh(x);
atof
f = atof(s);
atoi
i = atoi(s);
atol
l = atol(s);
basename
s = basename(path);
cabs
r = cabs(re, im);
cacos
(re, im) = cacos(re, im);
cacosh
(re, im) = cacosh(re, im);
carg
phi = carg(re, im);
casinh
(re, im) = casinh(re, im);
catan
(re, im) = catan(re, im);
catanh
(re, im) = catanh(re, im);
catclose
ret = catclose(catd);
catgets
s = catgets(catd, set_id, msg_id, dflt_string);
catopen
catd = catopen(name, oflag);
cbrt
y = cbrt(x);
ccos
(re, im) = ccos(re, im);
ccosh
(re, im) = ccosh(re, im);
ceil
y = ceil(x);
cexp
(re, im) = cexp(re, im);
chdir
ret = chdir(path);
chmod
ret = chmod(path, mode);
chown
ret = chown(path, uid, gid);
cimag
im = cimag(re, im);
clock
t = clock()
clock_getcpuclockid
clock_id = clock_getcpuclockid(pid);
pid defaults to $$. Returns undef on error.
clock_getres
(sec, nsec) = clock_getres(clock_id);
clock_id defaults to CLOCK_REALTIME. Returns empty list on error.
clock_gettime
(sec, nsec) = clock_gettime(clock_id);
clock_id defaults to CLOCK_REALTIME. Returns empty list on error.
clock_nanosleep
(rem_sec, rem_nsec) = clock_nanosleep(clock_id, flags, sec, nsec);
In scalar context returns the remaining seconds as a floating point number.
clock_settime
ret = clock_settime(clock_id, sec, nsec);
clog
(re, im) = clog(re, im);
close
ret = close(fd);
confstr
s = confstr(name);
name is one of the _CS_ integer constants.
conj
(re, im) = conj(re, im);
copysign
xs = copysign(x, y);
cos y = cos(x);
cosh
y = cosh(x);
cpow
(re, im) = cpow(re_x, im_x, re_y, im_y);
cproj
(re, im) = cproj(re, im);
creal
re = creal(re, im);
csin
(re, im) = csin(re, im);
csinh
(re, im) = csinh(re, im);
csqrt
(re, im) = csqrt(re, im);
ctan
(re, im) = ctan(re, im);
ctanh
(re, im) = ctanh(re, im);
dirname
name = dirname(path);
div (quot, rem) = div(numer, denom);
dlclose
dlclose(dlhandle);
dlerror
dlerror();
dlopen
dlhandle = dlopen(file, mode);
dlsym
addr = dlsym(dlhandle, name);
drand48
r = drand48();
endutxent
endutxent();
erand48
(r, X0, X1, X2) = erand48(X0, X1, X2);
erf y = erf(x);
erfc
y = erfc(x);
exp2
y = exp2(x);
expm1
y = expm1(x);
faccessat
ret = faccessat(dirfd, path, amode, flags=0);
flags is the bitwise OR of zero or more of AT_EACCESS, AT_SYMLINK_NOFOLLOW.
fchdir
ret = fchdir(dirfd);
fchmod
ret = fchmod(fd, mode);
fchmodat
ret = fchmodat(dirfd, path, mode, flags=0);
flags can be 0 or AT_SYMLINK_NOFOLLOW.
fchown
ret = fchown(fd, uid, gid);
fchownat
ret = fchownat(dirfd, path, uid, gid, flags=0);
flags can be 0 or AT_SYMLINK_NOFOLLOW.
fdatasync
ret = fdatasync(fd);
fdopen
ret = fdopen(fd, mode)
Returns a file handle associated with the file descriptor fd or undef on error. mode is one of the
values "r", "w", "a" with an optional "+" and/or "b".
It's similar to "IO::Handle::new_from_fd()" with the following improvements:
• It really calls fdopen(3).
• It expects POSIX mode strings (e.g. "r", not "<").
• It fails mode is not compatible with the flags of fd.
fdopendir
ret = fdopendir(fd)
Returns a directory handle associated with the file descriptor fd or undef on error. Usage example:
my $dh = do {
sysopen my $fh, '/tmp', O_RDONLY|O_DIRECTORY|O_NOFOLLOW;
fdopendir($fh); # or fdopendir(fileno $fh) but the former also works
# with handles from opendir() for which fileno does
# not work before Perl 5.22
};
my @files = readdir $dh; # this would fail with $fh from sysopen
fdim
d = fdim(double x, double y);
fegetround
round = fegetround();
fesetround
ret = fesetround(round);
ffs pos = ffs(i);
floor
y = floor(x);
fma r = fma(x, y, z);
fmax
m = fmax(x, y);
fmin
m = fmin(x, y);
fmod
m = fmod(x, y);
fnmatch
ret = fnmatch(pattern, string, flags);
Returns 0 if string matches pattern, FNM_NOMATCH if there is no match, undef if there is an error.
flags is the bitwise OR of zero or more of FNM_NOESCAPE, FNM_PATHNAME, FNM_PERIOD, FNM_FILE_NAME,
FNM_LEADING_DIR, FNM_CASEFOLD.
fpclassify
fpclassify(x);
Returns one of FP_NAN, FP_INFINITE, FP_ZERO, FP_SUBNORMAL, FP_NORMAL.
fstatat
(dev, ino, mode, nlink, uid, gid, rdev, size, atim_sec, mtim_sec, ctim_sec, blksize, blocks,
atim_nsec, mtim_nsec, ctim_nsec) = fstatat(dirfd, path, flags = 0);
flags is the bitwise OR of zero or more of AT_SYMLINK_NOFOLLOW, AT_NO_AUTOMOUNT.
fsync
ret = fsync(fd);
ftruncate
ret = ftruncate(fd, length);
futimens
ret = futimens(fd, atime_sec, atime_nsec, mtime_sec, mtime_nsec);
atime_sec and mtime_sec default to 0, atime_nsec and mtime_nsec default to UTIME_NOW.
getdate
(sec, min, hour, mday, mon, year, wday, yday, isdst) = getdate(string);
getdate_err
getdate_err() returns the value of the getdate_err variable.
getegid
egid = getegid();
geteuid
euid = geteuid();
getgid
gid = getgid();
gethostid
hostid = gethostid();
gethostname
hostname = gethostname();
getitimer
(int_sec, int_usec, val_sec, val_usec) = getitimer(which);
which is one of ITIMER_REAL, ITIMER_VIRTUAL, ITIMER_PROF.
getpriority
prio = getpriority(which, who);
which can be one of PRIO_PROCESS, PRIO_PGRP, PRIO_USER, defaults to PRIO_PROCESS.
who defaults to 0.
Returns undef on error.
getsid
sid = getsid(pid);
pid defaults to 0.
getuid
uid = getuid();
getutxent
(user, id, line, pid, type, sec, usec) = getutxent();
getutxent() reads a line from the current file position in the utmp file.
getutxid
(user, id, line, pid, type, sec, usec) = getutxid(ut_type, ut_id);
getutxid() searches forward from the current file position in the utmp file based upon ut_type and
ut_id. If ut_type is one of RUN_LVL, BOOT_TIME, NEW_TIME, or OLD_TIME, getutxid() will find the first
entry whose ut_type field matches ut_type. If ut_type is one of INIT_PROCESS, LOGIN_PROCESS,
USER_PROCESS, or DEAD_PROCESS, getutxid() will find the first entry whose ut_id field matches ut_id.
getutxline
(user, id, line, pid, type, sec, usec) = getutxline(ut_line);
getutxline() searches forward from the current file position in the utmp file. It scans entries
whose ut_type is USER_PROCESS or LOGIN_PROCESS and returns the first one whose ut_line field matches
ut_line.
hypot
r = hypot(x, y);
ilogb
y = ilogb(x);
isalpha
Like POSIX::isalpha() but returns 0 for the empty string.
isatty
ret = isatty(fd)
isblank
ret = isblank(charstring)
Returns 1 if charstring consists only of blank characters (i.e. spaces and/or tabs). Returns 0
otherwise (also for the empty string).
iscntrl
Like POSIX::iscntrl() but returns 0 for the empty string.
isdigit
Like POSIX::isdigit() but returns 0 for the empty string.
isfinite
isfinite(x);
isgraph
Like POSIX::isgraph() but returns 0 for the empty string.
isinf
isinf(x);
islower
Like POSIX::islower() but returns 0 for the empty string.
isnan
isnan(x);
isnormal
isnormal(x);
isprint
Like POSIX::isprint() but returns 0 for the empty string.
ispunct
Like POSIX::ispunct() but returns 0 for the empty string.
isspace
Like POSIX::isspace() but returns 0 for the empty string.
isupper
Like POSIX::isupper() but returns 0 for the empty string.
isxdigit
Like POSIX::isxdigit() but returns 0 for the empty string.
j0 y = j0(x);
j0() is the Bessel function of the first kind of order 0.
j1 y = j1(x);
j1() is the Bessel function of the first kind of order 1.
jn y = jn(n, x);
jn() is the Bessel function of the first kind of order n.
jrand48
(r, X0, X1, X2) = jrand48(X0, X1, X2);
killpg
ret = killpg(pgrp, sig);
l64a
s = l64a(n);
lchown
ret = lchown(path, uid, gid)
ldexp
y = ldexp(x, exp);
ldiv
(quot, rem) = ldiv(numer, denom);
lgamma
y = lgamma(x);
link
ret = link(path1, path2);
linkat
ret = linkat(fd1, path1, fd2, path2, flags=0);
flags can be 0 or AT_SYMLINK_FOLLOW.
log1p
y = log1p(x);
log2
y = log2(x);
logb
y = logb(x);
lrand48
r = lrand48();
lround
l = lround(x)
lstat
ret = lstat(path);
mkdir
ret = mkdir(path, mode);
mkdirat
ret = mkdirat(fd, path, mode);
mkdtemp
name = mkdtemp(template);
mkfifo
ret = mkfifo(path, mode);
mkfifoat
ret = mkfifoat(fd, path, mode);
mknod
ret = mknod(path, mode, dev);
mknodat
ret = mknodat(fd, path, mode, dev);
mkstemp
(fd, name) = mkstemp(template);
mrand48
mrand48();
nanosleep
(rem_sec, rem_nsec) = nanosleep(sec, nsec);
In scalar context returns the remaining seconds as a floating point number.
nearbyint
y = nearbyint(x);
nextafter
z = nextafter(x, y);
nrand48
r = nrand48()
open
ret = open(path, oflag[, mode]);
oflag defaults to O_RDONLY, mode defaults to 0600.
openat
ret = openat(fd, path, oflag[, mode]);
oflag defaults to O_RDONLY, mode defaults to 0600.
If fd is numeric (i.e. a file descriptor), "openat()" returns a file descriptor. If fd is a file or
directory handle the return value is also a handle whose type depends on the file type of path: If
path is a directory, the return value is a directory handle, otherwise it's a file handle.
Returns undef on error.
posix_fadvise
ret = posix_fadvise(fd, offset, len, advice);
advice is one of the "POSIX_FADV_" constants.
Returns undef on error
posix_fallocate
ret = posix_fallocate(fd, offset, len);
pread
bytes_read = pread(fd, buf, count, [offset, buf_offset]);
"pread()" reads count bytes (not characters) of data from the file descriptor fd at file offset
offset into the scalar buf without changing the file offset. buf will be enlarged automatically if
necessary.
offset and buf_offset are set to 0 if omitted or undef.
"pread()" treats buf just like "sysread()" does: buf_offset may be specified to place the read data
at that position in buf. If buf_offset is past the end of buf, buf will be padded with zeros before
appending the data. If buf_offset is negative, it is counted from the end of the string. buf will be
grown or shrunk so that the last byte actually read is the last byte of buf after the read.
Returns the number of bytes read, 0 at EOF, undef on error.
preadv
bytes_read = preadv(fd, buffers, sizes, [offset])
"preadv()" behaves like "readv()" but adds an optional offset argument, which specifies the file
position at which the data is to be read. offset is set to 0 if omitted or undef.
The file offset is not changed by this system call. The file referred to by fd must be capable of
seeking.
ptsname
name = ptsname(fd);
pwrite
bytes_written = pwrite(fd, buf, [count, offset, buf_offset]);
pwrite() writes count bytes of data from the scalar buf to the file descriptor fd at file offset
offset without changing the file offset. The file referenced by fd must be capable of seeking.
If count is omitted or undef, everything from buf_offset up to the end of buf is written.
buf_offset may be specified to write data from that position in buf. If buf_offset is negative it is
counted from the end of the string.
offset and buf_offset are set to 0 if omitted or undef.
Returns the number of bytes written, undef on error.
On Linux, if a file is opened with O_APPEND, pwrite() appends data to the end of the file, regardless
of the value of offset (in violation of POSIX).
pwritev
bytes_written = pwritev(fd, buffers, [offset])
"pwritev()" behaves like "writev()" but adds an optional offset argument, which specifies the file
position at which the data is to be written. offset is set to 0 if omitted or undef.
The file offset is not changed by this system call. The file referred to by fd must be capable of
seeking.
random
r = random();
read
bytes_read = read(fd, buf, count);
Like POSIX::read() but returns 0 at EOF instead of "0 but true".
readv
bytes_read = readv(fd, buffers, sizes);
Example:
sysopen my $fh, '/tmp/foobar', O_RDWR|O_CREAT|O_TRUNC;
pwrite($fh, 'foobar', 6, 0);
readv($fh, my @buf, [4, 0, 4, 4]);
# -> @buf is ('foob', '', 'ar')
"readv()" reads from the file descriptor fd into buffers as many strings as there are elements in
sizes. buffers must be a variable holding an array or an array reference. sizes must be an array
reference.
sizes is expected to hold unsigned integers that specify how many bytes are to be read into each
buffer. A byte count of 0 or undef creates an empty string. sizes is processed in array order.
buffers will be extended if necessary, but it will never be shrunk. If buffers is not empty, any
existing elements are replaced as long as sufficient data was read from fd.
If the total byte count of sizes exceeds the number of bytes actually read from fd, there may be one
partly filled buffer and the rest of sizes is skipped, so you may end up with less strings in buffers
than there are elements in sizes.
"readv()" returns the number of bytes read (which may be less than the total bytes in sizes) or undef
on error.
readlink
name = readlink(path);
Returns undef on error.
readlinkat
name = readlinkat(dirfd, path);
Returns undef on error.
remainder
r = remainder(x, y);
remove
ret = remove(path);
Calls the actual C library function "remove()".
Note that POSIX::remove() fails if path is a symlink to a directory because someone "couldn't read
the plans right and did a piss-poor job of putting it together" as "(-d $_[0]) ? CORE::rmdir($_[0]) :
CORE::unlink($_[0])". Quote from Armageddon.
rename
ret = rename(old, new);
renameat
ret = renameat(olddirfd, oldpath, newdirfd, newpath);
round
r = round(x);
scalbn
y = scalbn(x, n);
seed48
(old_seed1, old_seed2, old_seed3) = seed48(seed1, seed2, seed3);
setegid
ret = setegid(gid);
seteuid
ret = seteuid(uid);
setgid
ret = setgid(gid);
setitimer
(old_int_sec, old_int_usec, old_val_sec, old_val_usec) = setitimer(which, int_sec, int_usec, val_sec,
val_usec);
which is one of ITIMER_REAL, ITIMER_VIRTUAL, ITIMER_PROF.
setpriority
ret = setpriority(value, which, who);
which can be one of PRIO_PROCESS, PRIO_PGRP, PRIO_USER, defaults to PRIO_PROCESS.
Returns true on success, undef on error.
who defaults to 0.
setregid
ret = setregid(rgid, egid);
setreuid
ret = setreuid(ruid, euid);
setuid
ret = setuid(uid);
setutxent
setutxent();
sighold
ret = sighold(sig);
sigignore
ret = sigignore(sig);
signbit
b = signbit(x);
sigpause
sigpause(sig);
sigrelse
ret = sigrelse(sig);
sinh
y = sinh(x);
srand48
srand48(seedval);
srandom
srandom(seed);
stat
(dev, ino, mode, nlink, uid, gid, rdev, size, atim_sec, mtim_sec, ctim_sec, blksize, blocks,
atim_nsec, mtim_nsec, ctim_nsec) = stat(path);
strptime
(sec, min, hour, mday, mon, year, wday, yday, isdst) = strptime(s, format[, sec, min, hour, mday,
mon, year, wday, yday, isdst]);
strptime() converts the string s into a broken-down time according to the format string format. The
time fields may optionally be initialized in whole or in part and will be returned as initialized if
they are not affected by the format string. Unprocessed uninitialized or undef fields are returned as
undef.
Returns an empty list on error.
In scalar context returns the index of the first byte in s that was not processed or the byte length
of s if the whole string was consumed or undef on error.
As strptime() acts on null-terminated strings, strings containing NUL bytes will only be processed up
to the first NUL byte.
symlink
symlink(old, new);
symlinkat
ret = symlinkat(old, dirfd, new);
sync
sync();
tan y = tan(x);
tanh
y = tanh(x);
tgamma
y = tgamma(x);
timer_create
timerid = timer_create(clockid, signal);
Returns undef on error.
timer_delete
timer_delete(timerid);
Returns '0 but true' on success, undef on error.
timer_getoverrun
count = timer_getoverrun(timerid);
Returns undef on error.
timer_gettime
(interval_sec, interval_nsec, initial_sec, initial_nsec) = timer_gettime(timerid);
Returns an empty list on error.
timer_settime
(old_int_sec, old_int_nsec, old_init_sec, old_init_nsec) = timer_settime(timerid, flags, int_sec,
int_nsec, [init_sec, init_nsec]);
flags may be 0 or "TIMER_ABSTIME". If the init values are omitted, they are set to the int values.
truncate
ret = truncate(path, length);
trunc
y = trunc(x);
unlinkat
ret = unlinkat(dirfd, path, flags=0);
flags can be 0 or AT_REMOVEDIR.
unlink
ret = unlink(path);
utimensat
ret = utimensat(dirfd, path, flags, atime_sec, atime_nsec, mtime_sec, mtime_nsec);
flags can be 0 or AT_SYMLINK_NOFOLLOW, defaults to 0.
atime_sec and mtime_sec default to 0. atime_nsec and mtime_nsec default to UTIME_NOW.
write
bytes_written = write(fd, buf[, count]);
Like POSIX::write() but returns 0 instead of "0 but true" if 0 bytes were written, and it does not
write more bytes than buf contains.
If count is omitted or undef, it defaults to the length of buf.
writev
bytes_written = writev(fd, buffers);
writev() writes multiple buffers from buffers to the file associated with the file descriptor fd.
buffers must be an array reference. The buffers are processed in array order. Undefined or empty
elements are skipped.
Returns the number of bytes written or undef on error.
y0 y = y0(x);
y0() is the Bessel function of the second kind of order 0.
y1 y = y1(x);
y1() is the Bessel function of the second kind of order 1.
yn y = yn(n, x);
yn() is the Bessel function of the second kind of order n.
EXPORTS
This module does not export anything by default. The following export tags are available:
:at All *at() functions like openat() etc. plus all AT_ constants
:id All get/set*id() functions like getuid() etc.
:is All is* functions like isdigit() etc.
:rw read(), readv(), write(), writev()
:prw pread(), preadv(), pwrite(), pwritev()
:clock All clock* functions and all CLOCK* constants
:fcntl All F_, FD_, O_, POSIX_FADV_ and SEEK_ constants (for AT_ use :at)
:fnm C<fnmatch()> and all FNM_ constants
:time_h All CLOCK_ and TIMER_ constants
:timer All timer_ functions and TIMER_ constants
CONSTANTS
"AT_EACCESS" "AT_EMPTY_PATH" "AT_FDCWD" "AT_NO_AUTOMOUNT" "AT_REMOVEDIR" "AT_SYMLINK_FOLLOW"
"AT_SYMLINK_NOFOLLOW"
"BOOT_TIME" "NEW_TIME" "OLD_TIME" "DEAD_PROCESS" "INIT_PROCESS" "LOGIN_PROCESS" "USER_PROCESS" "RUN_LVL"
"CLOCK_BOOTTIME" "CLOCK_HIGHRES" "CLOCK_MONOTONIC" "CLOCK_MONOTONIC_COARSE" "CLOCK_MONOTONIC_FAST"
"CLOCK_MONOTONIC_PRECISE" "CLOCK_MONOTONIC_RAW" "CLOCK_PROCESS_CPUTIME_ID" "CLOCK_REALTIME"
"CLOCK_REALTIME_COARSE" "CLOCK_REALTIME_FAST" "CLOCK_REALTIME_PRECISE" "CLOCK_SOFTTIME"
"CLOCK_THREAD_CPUTIME_ID" "CLOCK_UPTIME" "CLOCK_UPTIME_FAST" "CLOCK_UPTIME_PRECISE"
"_CS_GNU_LIBC_VERSION" "_CS_GNU_LIBPTHREAD_VERSION" "_CS_PATH"
"F_DUPFD" "F_DUPFD_CLOEXEC" "F_GETFD" "F_SETFD" "F_GETFL" "F_SETFL" "F_GETLK" "F_SETLK" "F_SETLKW"
"F_GETOWN" "F_SETOWN" "F_RDLCK" "F_UNLCK" "F_WRLCK"
"FD_CLOEXEC"
"FNM_CASEFOLD" "FNM_FILE_NAME" "FNM_LEADING_DIR" "FNM_NOESCAPE" "FNM_NOMATCH" "FNM_PATHNAME" "FNM_PERIOD"
"FP_INFINITE" "FP_NAN" "FP_NORMAL" "FP_SUBNORMAL" "FP_ZERO"
"TIMER_ABSTIME" "ITIMER_PROF" "ITIMER_REAL" "ITIMER_VIRTUAL"
"O_ACCMODE" "O_APPEND" "O_CLOEXEC" "O_CREAT" "O_DIRECTORY" "O_DSYNC" "O_EXEC" "O_NOCTTY" "O_NOFOLLOW"
"O_NONBLOCK" "O_RDONLY" "O_RDWR" "O_RSYNC" "O_SEARCH" "O_SYNC" "O_TMPFILE" "O_TRUNC" "O_TTY_INIT"
"O_WRONLY"
"POSIX_FADV_NORMAL" "POSIX_FADV_SEQUENTIAL" "POSIX_FADV_RANDOM" "POSIX_FADV_NOREUSE"
"POSIX_FADV_WILLNEED" "POSIX_FADV_DONTNEED"
"RTLD_GLOBAL" "RTLD_LAZY" "RTLD_LOCAL" "RTLD_NOW"
"SEEK_SET" "SEEK_CUR" "SEEK_END"
"UTIME_NOW" "UTIME_OMIT"
NOTES
For whatever reason, "preadv()" and "pwritev()" are not part of POSIX. They are included anyway.
AUTHOR
Initially hacked together by Carsten Gaebler.
LICENSE
This library is free software. You can redistribute and/or modify it under the terms of the Do What The
Fuck You Want To Public License, Version 2, as published by Sam Hocevar. See the COPYING file or
http://www.wtfpl.net/ for more details.
perl v5.26.1 2017-09-21 POSIX::2008(3pm)