1POSIX::2008(3)        User Contributed Perl Documentation       POSIX::2008(3)
2
3
4

NAME

6       POSIX::2008 - Perl interface to POSIX.1-2008
7

SYNOPSIS

9         use Fcntl;
10         use POSIX::2008 qw(openat pwrite);
11
12         sysopen my $dh, '/tmp', O_RDONLY|O_DIRECTORY|O_NOFOLLOW or die 'Dafuq?';
13         my $fh = openat($dh, 'foobar', O_RDWR|O_CREAT);
14         pwrite($fh, 'fuckyounsa', 10, 0);
15

DESCRIPTION

17       POSIX::2008 contains many of the interfaces specified by POSIX.1-2008
18       <http://pubs.opengroup.org/onlinepubs/9699919799/> that the core POSIX
19       module withholds, implements in Perl or fucked up.
20
21       This module is provided "as is" unless someone volunteers to maintain
22       it.
23

INCOMPATIBLE PARAMETER CHANGE

25       Since version 0.13, the parameter order of pread/pwrite is (count,
26       offset) as with the actual system calls instead of (offset, count).
27       Good luck.
28

FILE DESCRIPTORS AND HANDLES

30       Since version 0.05, all I/O functions that take numeric file
31       descriptors also accept Perl file or directory handles. "openat()" even
32       returns a handle if you passed it one.
33

SYSTEM CALL RETURN VALUES

35       A system call return value of -1 meaning "error" is mapped to undef.
36
37       A system call return value of 0 meaning "success" is mapped to "0 but
38       true".
39
40       For system calls where 0 does not just mean "success", 0 is returned
41       unchanged. These are "open()", "read()", "write()", "readv()",
42       "writev()", "pread()", "pwrite()", "preadv()", "pwritev()". "openat()"
43       gets a special treatment in this module, see below.
44

FUNCTIONS

46       a64l
47           l = a64l(s);
48
49       abort
50           abort();
51
52       abs ui = abs(i);
53
54       access
55           ret = access(path, mode);
56
57       acos
58           y = acos(x);
59
60       acosh
61           y = acosh(x);
62
63       alarm
64           remaining_sec = alarm(sec);
65
66       asin
67           y = asin(x);
68
69       asinh
70           y = asinh(x);
71
72       atan2
73           z = atan2(y, x);
74
75       atan
76           y = atan(x);
77
78       atanh
79           y = atanh(x);
80
81       atof
82           f = atof(s);
83
84       atoi
85           i = atoi(s);
86
87       atol
88           l = atol(s);
89
90       basename
91           s = basename(path);
92
93       cabs
94           r = cabs(re, im);
95
96       cacos
97           (re, im) = cacos(re, im);
98
99       cacosh
100           (re, im) = cacosh(re, im);
101
102       carg
103           phi = carg(re, im);
104
105       casinh
106           (re, im) = casinh(re, im);
107
108       catan
109           (re, im) = catan(re, im);
110
111       catanh
112           (re, im) = catanh(re, im);
113
114       catclose
115           ret = catclose(catd);
116
117       catgets
118           s = catgets(catd, set_id, msg_id, dflt_string);
119
120       catopen
121           catd = catopen(name, oflag);
122
123       cbrt
124           y = cbrt(x);
125
126       ccos
127           (re, im) = ccos(re, im);
128
129       ccosh
130           (re, im) = ccosh(re, im);
131
132       ceil
133           y = ceil(x);
134
135       cexp
136           (re, im) = cexp(re, im);
137
138       chdir
139           ret = chdir(path);
140
141       chmod
142           ret = chmod(path, mode);
143
144       chown
145           ret = chown(path, uid, gid);
146
147       cimag
148           im = cimag(re, im);
149
150       clock
151           t = clock()
152
153       clock_getcpuclockid
154           clock_id = clock_getcpuclockid(pid);
155
156           pid defaults to $$. Returns undef on error.
157
158       clock_getres
159           (sec, nsec) = clock_getres(clock_id);
160
161           clock_id defaults to CLOCK_REALTIME. Returns empty list on error.
162
163       clock_gettime
164           (sec, nsec) = clock_gettime(clock_id);
165
166           clock_id defaults to CLOCK_REALTIME. Returns empty list on error.
167
168       clock_nanosleep
169           (rem_sec, rem_nsec) = clock_nanosleep(clock_id, flags, sec, nsec);
170
171           In scalar context returns the remaining seconds as a floating point
172           number.
173
174       clock_settime
175           ret = clock_settime(clock_id, sec, nsec);
176
177       clog
178           (re, im) = clog(re, im);
179
180       close
181           ret = close(fd);
182
183       confstr
184           s = confstr(name);
185
186           name is one of the _CS_ integer constants.
187
188       conj
189           (re, im) = conj(re, im);
190
191       copysign
192           xs = copysign(x, y);
193
194       cos y = cos(x);
195
196       cosh
197           y = cosh(x);
198
199       cpow
200           (re, im) = cpow(re_x, im_x, re_y, im_y);
201
202       cproj
203           (re, im) = cproj(re, im);
204
205       creal
206           re = creal(re, im);
207
208       csin
209           (re, im) = csin(re, im);
210
211       csinh
212           (re, im) = csinh(re, im);
213
214       csqrt
215           (re, im) = csqrt(re, im);
216
217       ctan
218           (re, im) = ctan(re, im);
219
220       ctanh
221           (re, im) = ctanh(re, im);
222
223       dirname
224           name = dirname(path);
225
226       div (quot, rem) = div(numer, denom);
227
228       dlclose
229           dlclose(dlhandle);
230
231       dlerror
232           dlerror();
233
234       dlopen
235           dlhandle = dlopen(file, mode);
236
237       dlsym
238           addr = dlsym(dlhandle, name);
239
240       drand48
241           r = drand48();
242
243       endutxent
244           endutxent();
245
246       erand48
247           (r, X0, X1, X2) = erand48(X0, X1, X2);
248
249       erf y = erf(x);
250
251       erfc
252           y = erfc(x);
253
254       exp2
255           y = exp2(x);
256
257       expm1
258           y = expm1(x);
259
260       faccessat
261           ret = faccessat(dirfd, path, amode, flags=0);
262
263           flags is the bitwise OR of zero or more of AT_EACCESS,
264           AT_SYMLINK_NOFOLLOW.
265
266       fchdir
267           ret = fchdir(dirfd);
268
269       fchmod
270           ret = fchmod(fd, mode);
271
272       fchmodat
273           ret = fchmodat(dirfd, path, mode, flags=0);
274
275           flags can be 0 or AT_SYMLINK_NOFOLLOW.
276
277       fchown
278           ret = fchown(fd, uid, gid);
279
280       fchownat
281           ret = fchownat(dirfd, path, uid, gid, flags=0);
282
283           flags can be 0 or AT_SYMLINK_NOFOLLOW.
284
285       fdatasync
286           ret = fdatasync(fd);
287
288       fdopen
289           ret = fdopen(fd, mode)
290
291           Returns a file handle associated with the file descriptor fd or
292           undef on error. mode is one of the values "r", "w", "a" with an
293           optional "+" and/or "b".
294
295           It's similar to "IO::Handle::new_from_fd()" with the following
296           improvements:
297
298           •   It really calls fdopen(3).
299
300           •   It expects POSIX  mode strings (e.g. "r", not "<").
301
302           •   It fails mode is not compatible with the flags of fd.
303
304       fdopendir
305           ret = fdopendir(fd)
306
307           Returns a directory handle associated with the file descriptor fd
308           or undef on error. Usage example:
309
310             my $dh = do {
311               sysopen my $fh, '/tmp', O_RDONLY|O_DIRECTORY|O_NOFOLLOW;
312               fdopendir($fh); # or fdopendir(fileno $fh) but the former also works
313                               # with handles from opendir() for which fileno does
314                               # not work before Perl 5.22
315             };
316             my @files = readdir $dh;  # this would fail with $fh from sysopen
317
318       fdim
319           d = fdim(double x, double y);
320
321       fegetround
322           round = fegetround();
323
324       fesetround
325           ret = fesetround(round);
326
327       ffs pos = ffs(i);
328
329       floor
330           y = floor(x);
331
332       fma r = fma(x, y, z);
333
334       fmax
335           m = fmax(x, y);
336
337       fmin
338           m = fmin(x, y);
339
340       fmod
341           m = fmod(x, y);
342
343       fnmatch
344           ret = fnmatch(pattern, string, flags);
345
346           Returns 0 if string matches pattern, FNM_NOMATCH if there is no
347           match, undef if there is an error.
348
349           flags is the bitwise OR of zero or more of FNM_NOESCAPE,
350           FNM_PATHNAME, FNM_PERIOD, FNM_FILE_NAME, FNM_LEADING_DIR,
351           FNM_CASEFOLD.
352
353       fpclassify
354           fpclassify(x);
355
356           Returns one of FP_NAN, FP_INFINITE, FP_ZERO, FP_SUBNORMAL,
357           FP_NORMAL.
358
359       fstatat
360           (dev, ino, mode, nlink, uid, gid, rdev, size, atim_sec, mtim_sec,
361           ctim_sec, blksize, blocks, atim_nsec, mtim_nsec, ctim_nsec) =
362           fstatat(dirfd, path, flags = 0);
363
364           flags is the bitwise OR of zero or more of AT_SYMLINK_NOFOLLOW,
365           AT_NO_AUTOMOUNT.
366
367       fsync
368           ret = fsync(fd);
369
370       ftruncate
371           ret = ftruncate(fd, length);
372
373       futimens
374           ret = futimens(fd, atime_sec, atime_nsec, mtime_sec, mtime_nsec);
375
376           atime_sec and mtime_sec default to 0, atime_nsec and mtime_nsec
377           default to UTIME_NOW.
378
379       getdate
380           (sec, min, hour, mday, mon, year, wday, yday, isdst) =
381           getdate(string);
382
383       getdate_err
384           getdate_err() returns the value of the getdate_err variable.
385
386       getegid
387           egid = getegid();
388
389       geteuid
390           euid = geteuid();
391
392       getgid
393           gid = getgid();
394
395       gethostid
396           hostid = gethostid();
397
398       gethostname
399           hostname = gethostname();
400
401       getitimer
402           (int_sec, int_usec, val_sec, val_usec) = getitimer(which);
403
404           which is one of ITIMER_REAL, ITIMER_VIRTUAL, ITIMER_PROF.
405
406       getpriority
407           prio = getpriority(which, who);
408
409           which can be one of PRIO_PROCESS, PRIO_PGRP, PRIO_USER, defaults to
410           PRIO_PROCESS.
411
412           who defaults to 0.
413
414           Returns undef on error.
415
416       getsid
417           sid = getsid(pid);
418
419           pid defaults to 0.
420
421       getuid
422           uid = getuid();
423
424       getutxent
425           (user, id, line, pid, type, sec, usec) = getutxent();
426
427           getutxent() reads a line from the current file position in the utmp
428           file.
429
430       getutxid
431           (user, id, line, pid, type, sec, usec) = getutxid(ut_type, ut_id);
432
433           getutxid() searches forward from the current file position in the
434           utmp file based upon ut_type and ut_id. If ut_type is one of
435           RUN_LVL, BOOT_TIME, NEW_TIME, or OLD_TIME, getutxid() will find the
436           first entry whose ut_type field matches ut_type. If ut_type is one
437           of INIT_PROCESS, LOGIN_PROCESS, USER_PROCESS, or DEAD_PROCESS,
438           getutxid() will find the first entry whose ut_id field matches
439           ut_id.
440
441       getutxline
442           (user, id, line, pid, type, sec, usec) = getutxline(ut_line);
443
444           getutxline() searches forward from the current file position in the
445           utmp file.  It scans entries whose ut_type is USER_PROCESS or
446           LOGIN_PROCESS and returns the first one whose ut_line field matches
447           ut_line.
448
449       hypot
450           r = hypot(x, y);
451
452       ilogb
453           y = ilogb(x);
454
455       isalpha
456           Like POSIX::isalpha() but returns 0 for the empty string.
457
458       isatty
459           ret = isatty(fd)
460
461       isblank
462           ret = isblank(charstring)
463
464           Returns 1 if charstring consists only of blank characters (i.e.
465           spaces and/or tabs). Returns 0 otherwise (also for the empty
466           string).
467
468       iscntrl
469           Like POSIX::iscntrl() but returns 0 for the empty string.
470
471       isdigit
472           Like POSIX::isdigit() but returns 0 for the empty string.
473
474       isfinite
475           isfinite(x);
476
477       isgraph
478           Like POSIX::isgraph() but returns 0 for the empty string.
479
480       isinf
481           isinf(x);
482
483       islower
484           Like POSIX::islower() but returns 0 for the empty string.
485
486       isnan
487           isnan(x);
488
489       isnormal
490           isnormal(x);
491
492       isprint
493           Like POSIX::isprint() but returns 0 for the empty string.
494
495       ispunct
496           Like POSIX::ispunct() but returns 0 for the empty string.
497
498       isspace
499           Like POSIX::isspace() but returns 0 for the empty string.
500
501       isupper
502           Like POSIX::isupper() but returns 0 for the empty string.
503
504       isxdigit
505           Like POSIX::isxdigit() but returns 0 for the empty string.
506
507       j0  y = j0(x);
508
509           j0() is the Bessel function of the first kind of order 0.
510
511       j1  y = j1(x);
512
513           j1() is the Bessel function of the first kind of order 1.
514
515       jn  y = jn(n, x);
516
517           jn() is the Bessel function of the first kind of order n.
518
519       jrand48
520           (r, X0, X1, X2) = jrand48(X0, X1, X2);
521
522       killpg
523           ret = killpg(pgrp, sig);
524
525       l64a
526           s = l64a(n);
527
528       lchown
529           ret = lchown(path, uid, gid)
530
531       ldexp
532           y = ldexp(x, exp);
533
534       ldiv
535           (quot, rem) = ldiv(numer, denom);
536
537       lgamma
538           y = lgamma(x);
539
540       link
541           ret = link(path1, path2);
542
543       linkat
544           ret = linkat(fd1, path1, fd2, path2, flags=0);
545
546           flags can be 0 or AT_SYMLINK_FOLLOW.
547
548       log1p
549           y = log1p(x);
550
551       log2
552           y = log2(x);
553
554       logb
555           y = logb(x);
556
557       lrand48
558           r = lrand48();
559
560       lround
561           l = lround(x)
562
563       lstat
564           ret = lstat(path);
565
566       mkdir
567           ret = mkdir(path, mode);
568
569       mkdirat
570           ret = mkdirat(fd, path, mode);
571
572       mkdtemp
573           name = mkdtemp(template);
574
575       mkfifo
576           ret = mkfifo(path, mode);
577
578       mkfifoat
579           ret = mkfifoat(fd, path, mode);
580
581       mknod
582           ret = mknod(path, mode, dev);
583
584       mknodat
585           ret = mknodat(fd, path, mode, dev);
586
587       mkstemp
588           (fd, name) = mkstemp(template);
589
590       mrand48
591           mrand48();
592
593       nanosleep
594           (rem_sec, rem_nsec) = nanosleep(sec, nsec);
595
596           In scalar context returns the remaining seconds as a floating point
597           number.
598
599       nearbyint
600           y = nearbyint(x);
601
602       nextafter
603           z = nextafter(x, y);
604
605       nrand48
606           r = nrand48()
607
608       open
609           ret = open(path, oflag[, mode]);
610
611           oflag defaults to O_RDONLY, mode defaults to 0600.
612
613       openat
614           ret = openat(fd, path, oflag[, mode]);
615
616           oflag defaults to O_RDONLY, mode defaults to 0600.
617
618           If fd is numeric (i.e. a file descriptor), "openat()" returns a
619           file descriptor. If fd is a file or directory handle the return
620           value is also a handle whose type depends on the file type of path:
621           If path is a directory, the return value is a directory handle,
622           otherwise it's a file handle.
623
624           Returns undef on error.
625
626       posix_fadvise
627           ret = posix_fadvise(fd, offset, len, advice);
628
629           advice is one of the "POSIX_FADV_" constants.
630
631           Returns undef on error
632
633       posix_fallocate
634           ret = posix_fallocate(fd, offset, len);
635
636       pread
637           bytes_read = pread(fd, buf, count, [offset, buf_offset]);
638
639           "pread()" reads count bytes (not characters) of data from the file
640           descriptor fd at file offset offset into the scalar buf without
641           changing the file offset. buf will be enlarged automatically if
642           necessary.
643
644           offset and buf_offset are set to 0 if omitted or undef.
645
646           "pread()" treats buf just like "sysread()" does: buf_offset may be
647           specified to place the read data at that position in buf. If
648           buf_offset is past the end of buf, buf will be padded with zeros
649           before appending the data. If buf_offset is negative, it is counted
650           from the end of the string. buf will be grown or shrunk so that the
651           last byte actually read is the last byte of buf after the read.
652
653           Returns the number of bytes read, 0 at EOF, undef on error.
654
655       preadv
656           bytes_read = preadv(fd, buffers, sizes, [offset])
657
658           "preadv()" behaves like "readv()" but adds an optional offset
659           argument, which specifies the file position at which the data is to
660           be read. offset is set to 0 if omitted or undef.
661
662           The file offset is not changed by this system call. The file
663           referred to by fd must be capable of seeking.
664
665       ptsname
666           name = ptsname(fd);
667
668       pwrite
669           bytes_written = pwrite(fd, buf, [count, offset, buf_offset]);
670
671           pwrite() writes count bytes of data from the scalar buf to the file
672           descriptor fd at file offset offset without changing the file
673           offset. The file referenced by fd must be capable of seeking.
674
675           If count is omitted or undef, everything from buf_offset up to the
676           end of buf is written.
677
678           buf_offset may be specified to write data from that position in
679           buf. If buf_offset is negative it is counted from the end of the
680           string.
681
682           offset and buf_offset are set to 0 if omitted or undef.
683
684           Returns the number of bytes written, undef on error.
685
686           On Linux, if a file is opened with O_APPEND, pwrite() appends data
687           to the end of the file, regardless of the value of offset (in
688           violation of POSIX).
689
690       pwritev
691           bytes_written = pwritev(fd, buffers, [offset])
692
693           "pwritev()" behaves like "writev()" but adds an optional offset
694           argument, which specifies the file position at which the data is to
695           be written. offset is set to 0 if omitted or undef.
696
697           The file offset is not changed by this system call. The file
698           referred to by fd must be capable of seeking.
699
700       random
701           r = random();
702
703       read
704           bytes_read = read(fd, buf, count);
705
706           Like POSIX::read() but returns 0 at EOF instead of "0 but true".
707
708       readv
709           bytes_read = readv(fd, buffers, sizes);
710
711           Example:
712
713             sysopen my $fh, '/tmp/foobar', O_RDWR|O_CREAT|O_TRUNC;
714             pwrite($fh, 'foobar', 6, 0);
715             readv($fh, my @buf, [4, 0, 4, 4]);
716             # -> @buf is ('foob', '', 'ar')
717
718           "readv()" reads from the file descriptor fd into buffers as many
719           strings as there are elements in sizes. buffers must be a variable
720           holding an array or an array reference. sizes must be an array
721           reference.
722
723           sizes is expected to hold unsigned integers that specify how many
724           bytes are to be read into each buffer. A byte count of 0 or undef
725           creates an empty string. sizes is processed in array order.
726
727           buffers will be extended if necessary, but it will never be shrunk.
728           If buffers is not empty, any existing elements are replaced as long
729           as sufficient data was read from fd.
730
731           If the total byte count of sizes exceeds the number of bytes
732           actually read from fd, there may be one partly filled buffer and
733           the rest of sizes is skipped, so you may end up with less strings
734           in buffers than there are elements in sizes.
735
736           "readv()" returns the number of bytes read (which may be less than
737           the total bytes in sizes) or undef on error.
738
739       readlink
740           name = readlink(path);
741
742           Returns undef on error.
743
744       readlinkat
745           name = readlinkat(dirfd, path);
746
747           Returns undef on error.
748
749       remainder
750           r = remainder(x, y);
751
752       remove
753           ret = remove(path);
754
755           Calls the actual C library function "remove()".
756
757           Note that POSIX::remove() fails if path is a symlink to a directory
758           because someone "couldn't read the plans right and did a piss-poor
759           job of putting it together" as "(-d $_[0]) ? CORE::rmdir($_[0]) :
760           CORE::unlink($_[0])". Quote from Armageddon.
761
762       rename
763           ret = rename(old, new);
764
765       renameat
766           ret = renameat(olddirfd, oldpath, newdirfd, newpath);
767
768       round
769           r = round(x);
770
771       scalbn
772           y = scalbn(x, n);
773
774       seed48
775           (old_seed1, old_seed2, old_seed3) = seed48(seed1, seed2, seed3);
776
777       setegid
778           ret = setegid(gid);
779
780       seteuid
781           ret = seteuid(uid);
782
783       setgid
784           ret = setgid(gid);
785
786       setitimer
787           (old_int_sec, old_int_usec, old_val_sec, old_val_usec) =
788           setitimer(which, int_sec, int_usec, val_sec, val_usec);
789
790           which is one of ITIMER_REAL, ITIMER_VIRTUAL, ITIMER_PROF.
791
792       setpriority
793           ret = setpriority(value, which, who);
794
795           which can be one of PRIO_PROCESS, PRIO_PGRP, PRIO_USER, defaults to
796           PRIO_PROCESS.
797
798           Returns true on success, undef on error.
799
800           who defaults to 0.
801
802       setregid
803           ret = setregid(rgid, egid);
804
805       setreuid
806           ret = setreuid(ruid, euid);
807
808       setuid
809           ret = setuid(uid);
810
811       setutxent
812           setutxent();
813
814       sighold
815           ret = sighold(sig);
816
817       sigignore
818           ret = sigignore(sig);
819
820       signbit
821           b = signbit(x);
822
823       sigpause
824           sigpause(sig);
825
826       sigrelse
827           ret = sigrelse(sig);
828
829       sinh
830           y = sinh(x);
831
832       srand48
833           srand48(seedval);
834
835       srandom
836           srandom(seed);
837
838       stat
839           (dev, ino, mode, nlink, uid, gid, rdev, size, atim_sec, mtim_sec,
840           ctim_sec, blksize, blocks, atim_nsec, mtim_nsec, ctim_nsec) =
841           stat(path);
842
843       strptime
844           (sec, min, hour, mday, mon, year, wday, yday, isdst) = strptime(s,
845           format[, sec, min, hour, mday, mon, year, wday, yday, isdst]);
846
847           strptime() converts the string s into a broken-down time according
848           to the format string format. The time fields may optionally be
849           initialized in whole or in part and will be returned as initialized
850           if they are not affected by the format string. Unprocessed
851           uninitialized or undef fields are returned as undef.
852
853           Returns an empty list on error.
854
855           In scalar context returns the index of the first byte in s that was
856           not processed or the byte length of s if the whole string was
857           consumed or undef on error.
858
859           As strptime() acts on null-terminated strings, strings containing
860           NUL bytes will only be processed up to the first NUL byte.
861
862       symlink
863           symlink(old, new);
864
865       symlinkat
866           ret = symlinkat(old, dirfd, new);
867
868       sync
869           sync();
870
871       tan y = tan(x);
872
873       tanh
874           y = tanh(x);
875
876       tgamma
877           y = tgamma(x);
878
879       timer_create
880           timerid = timer_create(clockid, signal);
881
882           Returns undef on error.
883
884       timer_delete
885           timer_delete(timerid);
886
887           Returns '0 but true' on success, undef on error.
888
889       timer_getoverrun
890           count = timer_getoverrun(timerid);
891
892           Returns undef on error.
893
894       timer_gettime
895           (interval_sec, interval_nsec, initial_sec, initial_nsec) =
896           timer_gettime(timerid);
897
898           Returns an empty list on error.
899
900       timer_settime
901           (old_int_sec, old_int_nsec, old_init_sec, old_init_nsec) =
902           timer_settime(timerid, flags, int_sec, int_nsec, [init_sec,
903           init_nsec]);
904
905           flags may be 0 or "TIMER_ABSTIME". If the init values are omitted,
906           they are set to the int values.
907
908       truncate
909           ret = truncate(path, length);
910
911       trunc
912           y = trunc(x);
913
914       unlinkat
915           ret = unlinkat(dirfd, path, flags=0);
916
917           flags can be 0 or AT_REMOVEDIR.
918
919       unlink
920           ret = unlink(path);
921
922       utimensat
923           ret = utimensat(dirfd, path, flags, atime_sec, atime_nsec,
924           mtime_sec, mtime_nsec);
925
926           flags can be 0 or AT_SYMLINK_NOFOLLOW, defaults to 0.
927
928           atime_sec and mtime_sec default to 0. atime_nsec and mtime_nsec
929           default to UTIME_NOW.
930
931       write
932           bytes_written = write(fd, buf[, count]);
933
934           Like POSIX::write() but returns 0 instead of "0 but true" if 0
935           bytes were written, and it does not write more bytes than buf
936           contains.
937
938           If count is omitted or undef, it defaults to the length of buf.
939
940       writev
941           bytes_written = writev(fd, buffers);
942
943           writev() writes multiple buffers from buffers to the file
944           associated with the file descriptor fd. buffers must be an array
945           reference. The buffers are processed in array order. Undefined or
946           empty elements are skipped.
947
948           Returns the number of bytes written or undef on error.
949
950       y0  y = y0(x);
951
952           y0() is the Bessel function of the second kind of order 0.
953
954       y1  y = y1(x);
955
956           y1() is the Bessel function of the second kind of order 1.
957
958       yn  y = yn(n, x);
959
960           yn() is the Bessel function of the second kind of order n.
961

EXPORTS

963       This module does not export anything by default. The following export
964       tags are available:
965
966        :at     All *at() functions like openat() etc. plus all AT_ constants
967        :id     All get/set*id() functions like getuid() etc.
968        :is     All is* functions like isdigit() etc.
969        :rw     read(), readv(), write(), writev()
970        :prw    pread(), preadv(), pwrite(), pwritev()
971        :clock  All clock* functions and all CLOCK* constants
972        :fcntl  All F_, FD_, O_, POSIX_FADV_ and SEEK_ constants (for AT_ use :at)
973        :fnm    C<fnmatch()> and all FNM_ constants
974        :time_h All CLOCK_ and TIMER_ constants
975        :timer  All timer_ functions and TIMER_ constants
976

CONSTANTS

978       "AT_EACCESS" "AT_EMPTY_PATH" "AT_FDCWD" "AT_NO_AUTOMOUNT"
979       "AT_REMOVEDIR" "AT_SYMLINK_FOLLOW" "AT_SYMLINK_NOFOLLOW"
980
981       "BOOT_TIME" "NEW_TIME" "OLD_TIME" "DEAD_PROCESS" "INIT_PROCESS"
982       "LOGIN_PROCESS" "USER_PROCESS" "RUN_LVL"
983
984       "CLOCK_BOOTTIME" "CLOCK_HIGHRES" "CLOCK_MONOTONIC"
985       "CLOCK_MONOTONIC_COARSE" "CLOCK_MONOTONIC_FAST"
986       "CLOCK_MONOTONIC_PRECISE" "CLOCK_MONOTONIC_RAW"
987       "CLOCK_PROCESS_CPUTIME_ID" "CLOCK_REALTIME" "CLOCK_REALTIME_COARSE"
988       "CLOCK_REALTIME_FAST" "CLOCK_REALTIME_PRECISE" "CLOCK_SOFTTIME"
989       "CLOCK_THREAD_CPUTIME_ID" "CLOCK_UPTIME" "CLOCK_UPTIME_FAST"
990       "CLOCK_UPTIME_PRECISE"
991
992       "_CS_GNU_LIBC_VERSION" "_CS_GNU_LIBPTHREAD_VERSION" "_CS_PATH"
993
994       "F_DUPFD" "F_DUPFD_CLOEXEC" "F_GETFD" "F_SETFD" "F_GETFL" "F_SETFL"
995       "F_GETLK" "F_SETLK" "F_SETLKW" "F_GETOWN" "F_SETOWN" "F_RDLCK"
996       "F_UNLCK" "F_WRLCK"
997
998       "FD_CLOEXEC"
999
1000       "FNM_CASEFOLD" "FNM_FILE_NAME" "FNM_LEADING_DIR" "FNM_NOESCAPE"
1001       "FNM_NOMATCH" "FNM_PATHNAME" "FNM_PERIOD"
1002
1003       "FP_INFINITE" "FP_NAN" "FP_NORMAL" "FP_SUBNORMAL" "FP_ZERO"
1004
1005       "TIMER_ABSTIME" "ITIMER_PROF" "ITIMER_REAL" "ITIMER_VIRTUAL"
1006
1007       "O_ACCMODE" "O_APPEND" "O_CLOEXEC" "O_CREAT" "O_DIRECTORY" "O_DSYNC"
1008       "O_EXEC" "O_NOCTTY" "O_NOFOLLOW" "O_NONBLOCK" "O_RDONLY" "O_RDWR"
1009       "O_RSYNC" "O_SEARCH" "O_SYNC" "O_TMPFILE" "O_TRUNC" "O_TTY_INIT"
1010       "O_WRONLY"
1011
1012       "POSIX_FADV_NORMAL" "POSIX_FADV_SEQUENTIAL" "POSIX_FADV_RANDOM"
1013       "POSIX_FADV_NOREUSE" "POSIX_FADV_WILLNEED" "POSIX_FADV_DONTNEED"
1014
1015       "RTLD_GLOBAL" "RTLD_LAZY" "RTLD_LOCAL" "RTLD_NOW"
1016
1017       "SEEK_SET" "SEEK_CUR" "SEEK_END"
1018
1019       "UTIME_NOW" "UTIME_OMIT"
1020

NOTES

1022       For whatever reason, "preadv()" and "pwritev()" are not part of POSIX.
1023       They are included anyway.
1024

AUTHOR

1026       Initially hacked together by Carsten Gaebler.
1027

LICENSE

1029       This library is free software. You can redistribute and/or modify it
1030       under the terms of the Do What The Fuck You Want To Public License,
1031       Version 2, as published by Sam Hocevar. See the COPYING file or
1032       http://www.wtfpl.net/ for more details.
1033
1034
1035
1036perl v5.34.0                      2022-01-21                    POSIX::2008(3)
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