1POSIX(3pm) Perl Programmers Reference Guide POSIX(3pm)
2
6 POSIX - Perl interface to IEEE Std 1003.1
7
9 use POSIX ();
10 use POSIX qw(setsid);
11 use POSIX qw(:errno_h :fcntl_h);
12 printf "EINTR is %d\n", EINTR;
14 my $sess_id = POSIX::setsid();
16 my $fd = POSIX::open($path, O_CREAT|O_EXCL|O_WRONLY, 0644);
18 # note: that's a filedescriptor, *NOT* a filehandle
19
21 The POSIX module permits you to access all (or nearly all) the standard
22 POSIX 1003.1 identifiers. Many of these identifiers have been given
23 Perl-ish interfaces.
24 This document gives a condensed list of the features available in the
26 POSIX module. Consult your operating system's manpages for general
27 information on most features. Consult perlfunc for functions which are
28 noted as being identical or almost identical to Perl's builtin
29 functions.
30 The first section describes POSIX functions from the 1003.1
32 specification. The second section describes some classes for signal
33 objects, TTY objects, and other miscellaneous objects. The remaining
34 sections list various constants and macros in an organization which
35 roughly follows IEEE Std 1003.1b-1993.
36 The notation "[C99]" indicates functions that were added in the ISO/IEC
38 9899:1999 version of the C language standard. Some may not be
39 available on your system if it adheres to an earlier standard.
40 Attempts to use any missing one will result in a fatal runtime error
41 message.
42
44 Everything is exported by default (with a handful of exceptions). This
45 is an unfortunate backwards compatibility feature and its use is
46 strongly discouraged. You should either prevent the exporting (by
47 saying "use POSIX ();", as usual) and then use fully qualified names
48 (e.g. "POSIX::SEEK_END"), or give an explicit import list. If you do
49 neither and opt for the default (as in "use POSIX;"), you will import
50 hundreds and hundreds of symbols into your namespace.
51 A few functions are not implemented because they are C specific. If
53 you attempt to call these, they will print a message telling you that
54 they aren't implemented, and suggest using the Perl equivalent, should
55 one exist. For example, trying to access the setjmp() call will elicit
56 the message ""setjmp() is C-specific: use eval {} instead"".
57 Furthermore, some evil vendors will claim 1003.1 compliance, but in
59 fact are not so: they will not pass the PCTS (POSIX Compliance Test
60 Suites). For example, one vendor may not define "EDEADLK", or the
61 semantics of the errno values set by open(2) might not be quite right.
62 Perl does not attempt to verify POSIX compliance. That means you can
63 currently successfully say "use POSIX", and then later in your program
64 you find that your vendor has been lax and there's no usable "ICANON"
65 macro after all. This could be construed to be a bug.
66
68 "_exit" This is identical to the C function _exit(). It exits the
69 program immediately which means among other things buffered I/O
70 is not flushed.
71 Note that when using threads and in Linux this is not a good
73 way to exit a thread because in Linux processes and threads are
74 kind of the same thing (Note: while this is the situation in
75 early 2003 there are projects under way to have threads with
76 more POSIXly semantics in Linux). If you want not to return
77 from a thread, detach the thread.
78 "abort" This is identical to the C function abort(). It terminates the
80 process with a "SIGABRT" signal unless caught by a signal
81 handler or if the handler does not return normally (it e.g.
82 does a "longjmp").
83 "abs" This is identical to Perl's builtin abs() function, returning
85 the absolute value of its numerical argument (except that
86 POSIX::abs() must be provided an explicit value (rather than
87 relying on an implicit $_):
88 $absolute_value = POSIX::abs(42); # good
90 $absolute_value = POSIX::abs(); # throws exception
92 "access"
94 Determines the accessibility of a file.
95 if( POSIX::access( "/", &POSIX::R_OK ) ){
97 print "have read permission\n";
98 }
99 Returns "undef" on failure. Note: do not use access() for
101 security purposes. Between the access() call and the operation
102 you are preparing for the permissions might change: a classic
103 race condition.
104 "acos" This is identical to the C function acos(), returning the arcus
106 cosine of its numerical argument. See also Math::Trig.
107 "acosh" This is identical to the C function acosh(), returning the
109 hyperbolic arcus cosine of its numerical argument [C99]. See
110 also Math::Trig. Added in Perl v5.22.
111 "alarm" This is identical to Perl's builtin alarm() function, either
113 for arming or disarming the "SIGARLM" timer, except that
114 POSIX::alarm() must be provided an explicit value (rather than
115 relying on an implicit $_):
116 POSIX::alarm(3) # good
118 POSIX::alarm() # throws exception
120 "asctime"
122 This is identical to the C function asctime(). It returns a
123 string of the form
124 "Fri Jun 2 18:22:13 2000\n\0"
126 and it is called thusly
128 $asctime = asctime($sec, $min, $hour, $mday, $mon,
130 $year, $wday, $yday, $isdst);
131 The $mon is zero-based: January equals 0. The $year is
133 1900-based: 2001 equals 101. $wday and $yday default to zero
134 (and are usually ignored anyway), and $isdst defaults to -1.
135 Note the result is always in English. Use "strftime" instead
137 to get a result suitable for the current locale. That
138 function's %c format yields the locale's preferred
139 representation.
140 "asin" This is identical to the C function asin(), returning the arcus
142 sine of its numerical argument. See also Math::Trig.
143 "asinh" This is identical to the C function asinh(), returning the
145 hyperbolic arcus sine of its numerical argument [C99]. See
146 also Math::Trig. Added in Perl v5.22.
147 "assert"
149 Unimplemented, but you can use "die" in perlfunc and the Carp
150 module to achieve similar things.
151 "atan" This is identical to the C function atan(), returning the arcus
153 tangent of its numerical argument. See also Math::Trig.
154 "atanh" This is identical to the C function atanh(), returning the
156 hyperbolic arcus tangent of its numerical argument [C99]. See
157 also Math::Trig. Added in Perl v5.22.
158 "atan2" This is identical to Perl's builtin atan2() function, returning
160 the arcus tangent defined by its two numerical arguments, the y
161 coordinate and the x coordinate. See also Math::Trig.
162 "atexit"
164 Not implemented. atexit() is C-specific: use "END {}" instead,
165 see perlmod.
166 "atof" Not implemented. atof() is C-specific. Perl converts strings
168 to numbers transparently. If you need to force a scalar to a
169 number, add a zero to it.
170 "atoi" Not implemented. atoi() is C-specific. Perl converts strings
172 to numbers transparently. If you need to force a scalar to a
173 number, add a zero to it. If you need to have just the integer
174 part, see "int" in perlfunc.
175 "atol" Not implemented. atol() is C-specific. Perl converts strings
177 to numbers transparently. If you need to force a scalar to a
178 number, add a zero to it. If you need to have just the integer
179 part, see "int" in perlfunc.
180 "bsearch"
182 bsearch() not supplied. For doing binary search on wordlists,
183 see Search::Dict.
184 "calloc"
186 Not implemented. calloc() is C-specific. Perl does memory
187 management transparently.
188 "cbrt" The cube root [C99]. Added in Perl v5.22.
190 "ceil" This is identical to the C function ceil(), returning the
192 smallest integer value greater than or equal to the given
193 numerical argument.
194 "chdir" This is identical to Perl's builtin chdir() function, allowing
196 one to change the working (default) directory -- see "chdir" in
197 perlfunc -- with the exception that POSIX::chdir() must be
198 provided an explicit value (rather than relying on an implicit
199 $_):
200 $rv = POSIX::chdir('path/to/dir'); # good
202 $rv = POSIX::chdir(); # throws exception
204 "chmod" This is identical to Perl's builtin chmod() function, allowing
206 one to change file and directory permissions -- see "chmod" in
207 perlfunc -- with the exception that POSIX::chmod() can only
208 change one file at a time (rather than a list of files):
209 $c = chmod 0664, $file1, $file2; # good
211 $c = POSIX::chmod 0664, $file1; # throws exception
213 $c = POSIX::chmod 0664, $file1, $file2; # throws exception
215 As with the built-in chmod(), $file may be a filename or a file
217 handle.
218 "chown" This is identical to Perl's builtin chown() function, allowing
220 one to change file and directory owners and groups, see "chown"
221 in perlfunc.
222 "clearerr"
224 Not implemented. Use the method IO::Handle::clearerr()
225 instead, to reset the error state (if any) and EOF state (if
226 any) of the given stream.
227 "clock" This is identical to the C function clock(), returning the
229 amount of spent processor time in microseconds.
230 "close" Close the file. This uses file descriptors such as those
232 obtained by calling "POSIX::open".
233 $fd = POSIX::open( "foo", &POSIX::O_RDONLY );
235 POSIX::close( $fd );
236 Returns "undef" on failure.
238 See also "close" in perlfunc.
240 "closedir"
242 This is identical to Perl's builtin closedir() function for
243 closing a directory handle, see "closedir" in perlfunc.
244 "cos" This is identical to Perl's builtin cos() function, for
246 returning the cosine of its numerical argument, see "cos" in
247 perlfunc. See also Math::Trig.
248 "cosh" This is identical to the C function cosh(), for returning the
250 hyperbolic cosine of its numeric argument. See also
251 Math::Trig.
252 "copysign"
254 Returns "x" but with the sign of "y" [C99]. Added in Perl
255 v5.22.
256 $x_with_sign_of_y = POSIX::copysign($x, $y);
258 See also "signbit".
260 "creat" Create a new file. This returns a file descriptor like the
262 ones returned by "POSIX::open". Use "POSIX::close" to close
263 the file.
264 $fd = POSIX::creat( "foo", 0611 );
266 POSIX::close( $fd );
267 See also "sysopen" in perlfunc and its "O_CREAT" flag.
269 "ctermid"
271 Generates the path name for the controlling terminal.
272 $path = POSIX::ctermid();
274 "ctime" This is identical to the C function ctime() and equivalent to
276 "asctime(localtime(...))", see "asctime" and "localtime".
277 "cuserid" [POSIX.1-1988]
279 Get the login name of the owner of the current process.
280 $name = POSIX::cuserid();
282 Note: this function has not been specified by POSIX since 1990
284 and is included only for backwards compatibility. New code
285 should use getlogin() instead.
286 "difftime"
288 This is identical to the C function difftime(), for returning
289 the time difference (in seconds) between two times (as returned
290 by time()), see "time".
291 "div" Not implemented. div() is C-specific, use "int" in perlfunc on
293 the usual "/" division and the modulus "%".
294 "dup" This is similar to the C function dup(), for duplicating a file
296 descriptor.
297 This uses file descriptors such as those obtained by calling
299 "POSIX::open".
300 Returns "undef" on failure.
302 "dup2" This is similar to the C function dup2(), for duplicating a
304 file descriptor to an another known file descriptor.
305 This uses file descriptors such as those obtained by calling
307 "POSIX::open".
308 Returns "undef" on failure.
310 "erf" The error function [C99]. Added in Perl v5.22.
312 "erfc" The complementary error function [C99]. Added in Perl v5.22.
314 "errno" Returns the value of errno.
316 $errno = POSIX::errno();
318 This identical to the numerical values of the $!, see "$ERRNO"
320 in perlvar.
321 "execl" Not implemented. execl() is C-specific, see "exec" in
323 perlfunc.
324 "execle"
326 Not implemented. execle() is C-specific, see "exec" in
327 perlfunc.
328 "execlp"
330 Not implemented. execlp() is C-specific, see "exec" in
331 perlfunc.
332 "execv" Not implemented. execv() is C-specific, see "exec" in
334 perlfunc.
335 "execve"
337 Not implemented. execve() is C-specific, see "exec" in
338 perlfunc.
339 "execvp"
341 Not implemented. execvp() is C-specific, see "exec" in
342 perlfunc.
343 "exit" This is identical to Perl's builtin exit() function for exiting
345 the program, see "exit" in perlfunc.
346 "exp" This is identical to Perl's builtin exp() function for
348 returning the exponent (e-based) of the numerical argument, see
349 "exp" in perlfunc.
350 "expm1" Equivalent to "exp(x) - 1", but more precise for small argument
352 values [C99]. Added in Perl v5.22.
353 See also "log1p".
355 "fabs" This is identical to Perl's builtin abs() function for
357 returning the absolute value of the numerical argument, see
358 "abs" in perlfunc.
359 "fclose"
361 Not implemented. Use method IO::Handle::close() instead, or
362 see "close" in perlfunc.
363 "fcntl" This is identical to Perl's builtin fcntl() function, see
365 "fcntl" in perlfunc.
366 "fdopen"
368 Not implemented. Use method IO::Handle::new_from_fd() instead,
369 or see "open" in perlfunc.
370 "feof" Not implemented. Use method IO::Handle::eof() instead, or see
372 "eof" in perlfunc.
373 "ferror"
375 Not implemented. Use method IO::Handle::error() instead.
376 "fflush"
378 Not implemented. Use method IO::Handle::flush() instead. See
379 also ""$OUTPUT_AUTOFLUSH" in perlvar".
380 "fgetc" Not implemented. Use method IO::Handle::getc() instead, or see
382 "read" in perlfunc.
383 "fgetpos"
385 Not implemented. Use method IO::Seekable::getpos() instead, or
386 see "seek" in perlfunc.
387 "fgets" Not implemented. Use method IO::Handle::gets() instead.
389 Similar to <>, also known as "readline" in perlfunc.
390 "fileno"
392 Not implemented. Use method IO::Handle::fileno() instead, or
393 see "fileno" in perlfunc.
394 "floor" This is identical to the C function floor(), returning the
396 largest integer value less than or equal to the numerical
397 argument.
398 "fdim" "Positive difference", "x - y" if "x > y", zero otherwise
400 [C99]. Added in Perl v5.22.
401 "fegetround"
403 Returns the current floating point rounding mode, one of
404 FE_TONEAREST FE_TOWARDZERO FE_UPWARD FE_DOWNWARD
406 "FE_TONEAREST" is like "round", "FE_TOWARDZERO" is like "trunc"
408 [C99]. Added in Perl v5.22.
409 "fesetround"
411 Sets the floating point rounding mode, see "fegetround" [C99].
412 Added in Perl v5.22.
413 "fma" "Fused multiply-add", "x * y + z", possibly faster (and less
415 lossy) than the explicit two operations [C99]. Added in Perl
416 v5.22.
417 my $fused = POSIX::fma($x, $y, $z);
419 "fmax" Maximum of "x" and "y", except when either is "NaN", returns
421 the other [C99]. Added in Perl v5.22.
422 my $max = POSIX::fmax($x, $y);
424 "fmin" Minimum of "x" and "y", except when either is "NaN", returns
426 the other [C99]. Added in Perl v5.22.
427 my $min = POSIX::fmin($x, $y);
429 "fmod" This is identical to the C function fmod().
431 $r = fmod($x, $y);
433 It returns the remainder "$r = $x - $n*$y", where
435 "$n = trunc($x/$y)". The $r has the same sign as $x and
436 magnitude (absolute value) less than the magnitude of $y.
437 "fopen" Not implemented. Use method IO::File::open() instead, or see
439 "open" in perlfunc.
440 "fork" This is identical to Perl's builtin fork() function for
442 duplicating the current process, see "fork" in perlfunc and
443 perlfork if you are in Windows.
444 "fpathconf"
446 Retrieves the value of a configurable limit on a file or
447 directory. This uses file descriptors such as those obtained
448 by calling "POSIX::open".
449 The following will determine the maximum length of the longest
451 allowable pathname on the filesystem which holds /var/foo.
452 $fd = POSIX::open( "/var/foo", &POSIX::O_RDONLY );
454 $path_max = POSIX::fpathconf($fd, &POSIX::_PC_PATH_MAX);
455 Returns "undef" on failure.
457 "fpclassify"
459 Returns one of
460 FP_NORMAL FP_ZERO FP_SUBNORMAL FP_INFINITE FP_NAN
462 telling the class of the argument [C99]. "FP_INFINITE" is
464 positive or negative infinity, "FP_NAN" is not-a-number.
465 "FP_SUBNORMAL" means subnormal numbers (also known as
466 denormals), very small numbers with low precision. "FP_ZERO" is
467 zero. "FP_NORMAL" is all the rest. Added in Perl v5.22.
468 "fprintf"
470 Not implemented. fprintf() is C-specific, see "printf" in
471 perlfunc instead.
472 "fputc" Not implemented. fputc() is C-specific, see "print" in
474 perlfunc instead.
475 "fputs" Not implemented. fputs() is C-specific, see "print" in
477 perlfunc instead.
478 "fread" Not implemented. fread() is C-specific, see "read" in perlfunc
480 instead.
481 "free" Not implemented. free() is C-specific. Perl does memory
483 management transparently.
484 "freopen"
486 Not implemented. freopen() is C-specific, see "open" in
487 perlfunc instead.
488 "frexp" Return the mantissa and exponent of a floating-point number.
490 ($mantissa, $exponent) = POSIX::frexp( 1.234e56 );
492 "fscanf"
494 Not implemented. fscanf() is C-specific, use <> and regular
495 expressions instead.
496 "fseek" Not implemented. Use method IO::Seekable::seek() instead, or
498 see "seek" in perlfunc.
499 "fsetpos"
501 Not implemented. Use method IO::Seekable::setpos() instead, or
502 seek "seek" in perlfunc.
503 "fstat" Get file status. This uses file descriptors such as those
505 obtained by calling "POSIX::open". The data returned is
506 identical to the data from Perl's builtin "stat" function.
507 $fd = POSIX::open( "foo", &POSIX::O_RDONLY );
509 @stats = POSIX::fstat( $fd );
510 "fsync" Not implemented. Use method IO::Handle::sync() instead.
512 "ftell" Not implemented. Use method IO::Seekable::tell() instead, or
514 see "tell" in perlfunc.
515 "fwrite"
517 Not implemented. fwrite() is C-specific, see "print" in
518 perlfunc instead.
519 "getc" This is identical to Perl's builtin getc() function, see "getc"
521 in perlfunc.
522 "getchar"
524 Returns one character from STDIN. Identical to Perl's getc(),
525 see "getc" in perlfunc.
526 "getcwd"
528 Returns the name of the current working directory. See also
529 Cwd.
530 "getegid"
532 Returns the effective group identifier. Similar to Perl' s
533 builtin variable $(, see "$EGID" in perlvar.
534 "getenv"
536 Returns the value of the specified environment variable. The
537 same information is available through the %ENV array.
538 "geteuid"
540 Returns the effective user identifier. Identical to Perl's
541 builtin $> variable, see "$EUID" in perlvar.
542 "getgid"
544 Returns the user's real group identifier. Similar to Perl's
545 builtin variable $), see "$GID" in perlvar.
546 "getgrgid"
548 This is identical to Perl's builtin getgrgid() function for
549 returning group entries by group identifiers, see "getgrgid" in
550 perlfunc.
551 "getgrnam"
553 This is identical to Perl's builtin getgrnam() function for
554 returning group entries by group names, see "getgrnam" in
555 perlfunc.
556 "getgroups"
558 Returns the ids of the user's supplementary groups. Similar to
559 Perl's builtin variable $), see "$GID" in perlvar.
560 "getlogin"
562 This is identical to Perl's builtin getlogin() function for
563 returning the user name associated with the current session,
564 see "getlogin" in perlfunc.
565 "getpayload"
567 use POSIX ':nan_payload';
568 getpayload($var)
569 Returns the "NaN" payload. Added in Perl v5.24.
571 Note the API instability warning in "setpayload".
573 See "nan" for more discussion about "NaN".
575 "getpgrp"
577 This is identical to Perl's builtin getpgrp() function for
578 returning the process group identifier of the current process,
579 see "getpgrp" in perlfunc.
580 "getpid"
582 Returns the process identifier. Identical to Perl's builtin
583 variable $$, see "$PID" in perlvar.
584 "getppid"
586 This is identical to Perl's builtin getppid() function for
587 returning the process identifier of the parent process of the
588 current process , see "getppid" in perlfunc.
589 "getpwnam"
591 This is identical to Perl's builtin getpwnam() function for
592 returning user entries by user names, see "getpwnam" in
593 perlfunc.
594 "getpwuid"
596 This is identical to Perl's builtin getpwuid() function for
597 returning user entries by user identifiers, see "getpwuid" in
598 perlfunc.
599 "gets" Returns one line from "STDIN", similar to <>, also known as the
601 readline() function, see "readline" in perlfunc.
602 NOTE: if you have C programs that still use gets(), be very
604 afraid. The gets() function is a source of endless grief
605 because it has no buffer overrun checks. It should never be
606 used. The fgets() function should be preferred instead.
607 "getuid"
609 Returns the user's identifier. Identical to Perl's builtin $<
610 variable, see "$UID" in perlvar.
611 "gmtime"
613 This is identical to Perl's builtin gmtime() function for
614 converting seconds since the epoch to a date in Greenwich Mean
615 Time, see "gmtime" in perlfunc.
616 "hypot" Equivalent to sqrt(x * x + y * y) except more stable on very
618 large or very small arguments [C99]. Added in Perl v5.22.
619 "ilogb" Integer binary logarithm [C99]. Added in Perl v5.22.
621 For example ilogb(20) is 4, as an integer.
623 See also "logb".
625 "Inf" The infinity as a constant:
627 use POSIX qw(Inf);
629 my $pos_inf = +Inf; # Or just Inf.
630 my $neg_inf = -Inf;
631 See also "isinf", and "fpclassify".
633 "isalnum"
635 This function has been removed as of Perl v5.24. It was very
636 similar to matching against "qr/ ^ [[:alnum:]]+ $ /x", which
637 you should convert to use instead. See "POSIX Character
638 Classes" in perlrecharclass.
639 "isalpha"
641 This function has been removed as of Perl v5.24. It was very
642 similar to matching against "qr/ ^ [[:alpha:]]+ $ /x", which
643 you should convert to use instead. See "POSIX Character
644 Classes" in perlrecharclass.
645 "isatty"
647 Returns a boolean indicating whether the specified filehandle
648 is connected to a tty. Similar to the "-t" operator, see "-X"
649 in perlfunc.
650 "iscntrl"
652 This function has been removed as of Perl v5.24. It was very
653 similar to matching against "qr/ ^ [[:cntrl:]]+ $ /x", which
654 you should convert to use instead. See "POSIX Character
655 Classes" in perlrecharclass.
656 "isdigit"
658 This function has been removed as of Perl v5.24. It was very
659 similar to matching against "qr/ ^ [[:digit:]]+ $ /x", which
660 you should convert to use instead. See "POSIX Character
661 Classes" in perlrecharclass.
662 "isfinite"
664 Returns true if the argument is a finite number (that is, not
665 an infinity, or the not-a-number) [C99]. Added in Perl v5.22.
666 See also "isinf", "isnan", and "fpclassify".
668 "isgraph"
670 This function has been removed as of Perl v5.24. It was very
671 similar to matching against "qr/ ^ [[:graph:]]+ $ /x", which
672 you should convert to use instead. See "POSIX Character
673 Classes" in perlrecharclass.
674 "isgreater"
676 (Also "isgreaterequal", "isless", "islessequal",
677 "islessgreater", "isunordered")
678 Floating point comparisons which handle the "NaN" [C99]. Added
680 in Perl v5.22.
681 "isinf" Returns true if the argument is an infinity (positive or
683 negative) [C99]. Added in Perl v5.22.
684 See also "Inf", "isnan", "isfinite", and "fpclassify".
686 "islower"
688 This function has been removed as of Perl v5.24. It was very
689 similar to matching against "qr/ ^ [[:lower:]]+ $ /x", which
690 you should convert to use instead. See "POSIX Character
691 Classes" in perlrecharclass.
692 "isnan" Returns true if the argument is "NaN" (not-a-number) [C99].
694 Added in Perl v5.22.
695 Note that you can also test for ""NaN"-ness" with equality
697 operators ("==" or "!="), as in
698 print "x is not a NaN\n" if $x == $x;
700 since the "NaN" is not equal to anything, including itself.
702 See also "nan", "NaN", "isinf", and "fpclassify".
704 "isnormal"
706 Returns true if the argument is normal (that is, not a
707 subnormal/denormal, and not an infinity, or a not-a-number)
708 [C99]. Added in Perl v5.22.
709 See also "isfinite", and "fpclassify".
711 "isprint"
713 This function has been removed as of Perl v5.24. It was very
714 similar to matching against "qr/ ^ [[:print:]]+ $ /x", which
715 you should convert to use instead. See "POSIX Character
716 Classes" in perlrecharclass.
717 "ispunct"
719 This function has been removed as of Perl v5.24. It was very
720 similar to matching against "qr/ ^ [[:punct:]]+ $ /x", which
721 you should convert to use instead. See "POSIX Character
722 Classes" in perlrecharclass.
723 "issignaling"
725 use POSIX ':nan_payload';
726 issignaling($var, $payload)
727 Return true if the argument is a signaling NaN. Added in Perl
729 v5.24.
730 Note the API instability warning in "setpayload".
732 See "nan" for more discussion about "NaN".
734 "isspace"
736 This function has been removed as of Perl v5.24. It was very
737 similar to matching against "qr/ ^ [[:space:]]+ $ /x", which
738 you should convert to use instead. See "POSIX Character
739 Classes" in perlrecharclass.
740 "isupper"
742 This function has been removed as of Perl v5.24. It was very
743 similar to matching against "qr/ ^ [[:upper:]]+ $ /x", which
744 you should convert to use instead. See "POSIX Character
745 Classes" in perlrecharclass.
746 "isxdigit"
748 This function has been removed as of Perl v5.24. It was very
749 similar to matching against "qr/ ^ [[:xdigit:]]+ $ /x", which
750 you should convert to use instead. See "POSIX Character
751 Classes" in perlrecharclass.
752 "j0"
754 "j1"
755 "jn"
756 "y0"
757 "y1"
758 "yn" The Bessel function of the first kind of the order zero.
759 "kill" This is identical to Perl's builtin kill() function for sending
761 signals to processes (often to terminate them), see "kill" in
762 perlfunc.
763 "labs" Not implemented. (For returning absolute values of long
765 integers.) labs() is C-specific, see "abs" in perlfunc
766 instead.
767 "lchown"
769 This is identical to the C function, except the order of
770 arguments is consistent with Perl's builtin chown() with the
771 added restriction of only one path, not a list of paths. Does
772 the same thing as the chown() function but changes the owner of
773 a symbolic link instead of the file the symbolic link points
774 to.
775 POSIX::lchown($uid, $gid, $file_path);
777 "ldexp" This is identical to the C function ldexp() for multiplying
779 floating point numbers with powers of two.
780 $x_quadrupled = POSIX::ldexp($x, 2);
782 "ldiv" Not implemented. (For computing dividends of long integers.)
784 ldiv() is C-specific, use "/" and int() instead.
785 "lgamma"
787 The logarithm of the Gamma function [C99]. Added in Perl
788 v5.22.
789 See also "tgamma".
791 "log1p" Equivalent to "log(1 + x)", but more stable results for small
793 argument values [C99]. Added in Perl v5.22.
794 "log2" Logarithm base two [C99]. Added in Perl v5.22.
796 See also "expm1".
798 "logb" Integer binary logarithm [C99]. Added in Perl v5.22.
800 For example logb(20) is 4, as a floating point number.
802 See also "ilogb".
804 "link" This is identical to Perl's builtin link() function for
806 creating hard links into files, see "link" in perlfunc.
807 "localeconv"
809 Get numeric formatting information. Returns a reference to a
810 hash containing the formatting values of the locale that
811 currently underlies the program, regardless of whether or not
812 it is called from within the scope of a "use locale". Users of
813 this function should also read perllocale, which provides a
814 comprehensive discussion of Perl locale handling, including a
815 section devoted to this function. Prior to Perl 5.28, or when
816 operating in a non thread-safe environment, it should not be
817 used in a threaded application unless it's certain that the
818 underlying locale is C or POSIX. This is because it otherwise
819 changes the locale, which globally affects all threads
820 simultaneously. Windows platforms starting with Visual Studio
821 2005 are mostly thread-safe, but use of this function in those
822 prior to Visual Studio 2015 can have a race with a thread that
823 has called "switch_to_global_locale" in perlapi.
824 Here is how to query the database for the de (Deutsch or
826 German) locale.
827 my $loc = POSIX::setlocale( &POSIX::LC_ALL, "de" );
829 print "Locale: \"$loc\"\n";
830 my $lconv = POSIX::localeconv();
831 foreach my $property (qw(
832 decimal_point
833 thousands_sep
834 grouping
835 int_curr_symbol
836 currency_symbol
837 mon_decimal_point
838 mon_thousands_sep
839 mon_grouping
840 positive_sign
841 negative_sign
842 int_frac_digits
843 frac_digits
844 p_cs_precedes
845 p_sep_by_space
846 n_cs_precedes
847 n_sep_by_space
848 p_sign_posn
849 n_sign_posn
850 int_p_cs_precedes
851 int_p_sep_by_space
852 int_n_cs_precedes
853 int_n_sep_by_space
854 int_p_sign_posn
855 int_n_sign_posn
856 ))
857 {
858 printf qq(%s: "%s",\n),
859 $property, $lconv->{$property};
860 }
861 The members whose names begin with "int_p_" and "int_n_" were
863 added by POSIX.1-2008 and are only available on systems that
864 support them.
865 A value of -1 returned for numeric entries indicates that the
867 field is not applicable to the locale. This is rare except in
868 the C and related locales, which don't have most monetary
869 values defined. It can also happen, quirkily, in fields that
870 are otherwise boolean to indicate that the value is kind of
871 neither true nor false. This happens in "p_cs_precedes" and
872 "int_p_cs_precedes" when the currency symbol neither precedes
873 nor succeeds a positive value but is infixed, by replacing the
874 radix character.
875 Prior to Perl v5.37.7, empty string fields and numeric fields
877 with value -1 were omittted from the returned hash.
878 "localtime"
880 This is identical to Perl's builtin localtime() function for
881 converting seconds since the epoch to a date see "localtime" in
882 perlfunc except that POSIX::localtime() must be provided an
883 explicit value (rather than relying on an implicit $_):
884 @localtime = POSIX::localtime(time); # good
886 @localtime = localtime(); # good
888 @localtime = POSIX::localtime(); # throws exception
890 "log" This is identical to Perl's builtin log() function, returning
892 the natural (e-based) logarithm of the numerical argument, see
893 "log" in perlfunc.
894 "log10" This is identical to the C function log10(), returning the
896 10-base logarithm of the numerical argument. You can also use
897 sub log10 { log($_[0]) / log(10) }
899 or
901 sub log10 { log($_[0]) / 2.30258509299405 }
903 or
905 sub log10 { log($_[0]) * 0.434294481903252 }
907 "longjmp"
909 Not implemented. longjmp() is C-specific: use "die" in
910 perlfunc instead.
911 "lseek" Move the file's read/write position. This uses file
913 descriptors such as those obtained by calling "POSIX::open".
914 $fd = POSIX::open( "foo", &POSIX::O_RDONLY );
916 $off_t = POSIX::lseek( $fd, 0, &POSIX::SEEK_SET );
917 Returns "undef" on failure.
919 "lrint" Depending on the current floating point rounding mode, rounds
921 the argument either toward nearest (like "round"), toward zero
922 (like "trunc"), downward (toward negative infinity), or upward
923 (toward positive infinity) [C99]. Added in Perl v5.22.
924 For the rounding mode, see "fegetround".
926 "lround"
928 Like "round", but as integer, as opposed to floating point
929 [C99]. Added in Perl v5.22.
930 See also "ceil", "floor", "trunc".
932 Owing to an oversight, this is not currently exported by
934 default, or as part of the ":math_h_c99" export tag; importing
935 it must therefore be done by explicit name.
936 "malloc"
938 Not implemented. malloc() is C-specific. Perl does memory
939 management transparently.
940 "mblen" This is the same as the C function mblen() on unthreaded perls.
942 On threaded perls, it transparently (almost) substitutes the
943 more thread-safe "mbrlen"(3), if available, instead of "mblen".
944 Core Perl does not have any support for wide and multibyte
946 locales, except Unicode UTF-8 locales. This function, in
947 conjunction with "mbtowc" and "wctomb" may be used to roll your
948 own decoding/encoding of other types of multi-byte locales.
949 Use "undef" as the first parameter to this function to get the
951 effect of passing NULL as the first parameter to "mblen". This
952 resets any shift state to its initial value. The return value
953 is undefined if "mbrlen" was substituted, so you should never
954 rely on it.
955 When the first parameter is a scalar containing a value that
957 either is a PV string or can be forced into one, the return
958 value is the number of bytes occupied by the first character of
959 that string; or 0 if that first character is the wide NUL
960 character; or negative if there is an error. This is based on
961 the locale that currently underlies the program, regardless of
962 whether or not the function is called from Perl code that is
963 within the scope of "use locale". Perl makes no attempt at
964 hiding from your code any differences in the "errno" setting
965 between "mblen" and "mbrlen". It does set "errno" to 0 before
966 calling them.
967 The optional second parameter is ignored if it is larger than
969 the actual length of the first parameter string.
970 "mbtowc"
972 This is the same as the C function mbtowc() on unthreaded
973 perls. On threaded perls, it transparently (almost)
974 substitutes the more thread-safe "mbrtowc"(3), if available,
975 instead of "mbtowc".
976 Core Perl does not have any support for wide and multibyte
978 locales, except Unicode UTF-8 locales. This function, in
979 conjunction with "mblen" and "wctomb" may be used to roll your
980 own decoding/encoding of other types of multi-byte locales.
981 The first parameter is a scalar into which, upon success, the
983 wide character represented by the multi-byte string contained
984 in the second parameter is stored. The optional third
985 parameter is ignored if it is larger than the actual length of
986 the second parameter string.
987 Use "undef" as the second parameter to this function to get the
989 effect of passing NULL as the second parameter to "mbtowc".
990 This ignores the first parameter, and resets any shift state to
991 its initial value. The return value is undefined if "mbrtowc"
992 was substituted, so you should never rely on it.
993 When the second parameter is a scalar containing a value that
995 either is a PV string or can be forced into one, the return
996 value is the number of bytes occupied by the first character of
997 that string; or 0 if that first character is the wide NUL
998 character; or negative if there is an error. This is based on
999 the locale that currently underlies the program, regardless of
1000 whether or not the function is called from Perl code that is
1001 within the scope of "use locale". Perl makes no attempt at
1002 hiding from your code any differences in the "errno" setting
1003 between "mbtowc" and "mbrtowc". It does set "errno" to 0
1004 before calling them.
1005 "memchr"
1007 Not implemented. memchr() is C-specific, see "index" in
1008 perlfunc instead.
1009 "memcmp"
1011 Not implemented. memcmp() is C-specific, use "eq" instead, see
1012 perlop.
1013 "memcpy"
1015 Not implemented. memcpy() is C-specific, use "=", see perlop,
1016 or see "substr" in perlfunc.
1017 "memmove"
1019 Not implemented. memmove() is C-specific, use "=", see perlop,
1020 or see "substr" in perlfunc.
1021 "memset"
1023 Not implemented. memset() is C-specific, use "x" instead, see
1024 perlop.
1025 "mkdir" This is identical to Perl's builtin mkdir() function for
1027 creating directories, see "mkdir" in perlfunc.
1028 "mkfifo"
1030 This is similar to the C function mkfifo() for creating FIFO
1031 special files.
1032 if (mkfifo($path, $mode)) { ....
1034 Returns "undef" on failure. The $mode is similar to the mode
1036 of mkdir(), see "mkdir" in perlfunc, though for "mkfifo" you
1037 must specify the $mode.
1038 "mktime"
1040 Convert date/time info to a calendar time.
1041 Synopsis:
1043 mktime(sec, min, hour, mday, mon, year, wday = 0,
1045 yday = 0, isdst = -1)
1046 The month ("mon"), weekday ("wday"), and yearday ("yday") begin
1048 at zero, i.e., January is 0, not 1; Sunday is 0, not 1; January
1049 1st is 0, not 1. The year ("year") is given in years since
1050 1900; i.e., the year 1995 is 95; the year 2001 is 101. Consult
1051 your system's mktime() manpage for details about these and the
1052 other arguments.
1053 Calendar time for December 12, 1995, at 10:30 am.
1055 $time_t = POSIX::mktime( 0, 30, 10, 12, 11, 95 );
1057 print "Date = ", POSIX::ctime($time_t);
1058 Returns "undef" on failure.
1060 "modf" Return the integral and fractional parts of a floating-point
1062 number.
1063 ($fractional, $integral) = POSIX::modf( 3.14 );
1065 See also "round".
1067 "NaN" The not-a-number as a constant:
1069 use POSIX qw(NaN);
1071 my $nan = NaN;
1072 See also "nan", "/isnan", and "fpclassify".
1074 "nan"
1076 my $nan = nan();
1077 Returns "NaN", not-a-number [C99]. Added in Perl v5.22.
1079 The returned NaN is always a quiet NaN, as opposed to
1081 signaling.
1082 With an argument, can be used to generate a NaN with payload.
1084 The argument is first interpreted as a floating point number,
1085 but then any fractional parts are truncated (towards zero), and
1086 the value is interpreted as an unsigned integer. The bits of
1087 this integer are stored in the unused bits of the NaN.
1088 The result has a dual nature: it is a NaN, but it also carries
1090 the integer inside it. The integer can be retrieved with
1091 "getpayload". Note, though, that the payload is not
1092 propagated, not even on copies, and definitely not in
1093 arithmetic operations.
1094 How many bits fit in the NaN depends on what kind of floating
1096 points are being used, but on the most common platforms (64-bit
1097 IEEE 754, or the x86 80-bit long doubles) there are 51 and 61
1098 bits available, respectively. (There would be 52 and 62, but
1099 the quiet/signaling bit of NaNs takes away one.) However,
1100 because of the floating-point-to- integer-and-back conversions,
1101 please test carefully whether you get back what you put in. If
1102 your integers are only 32 bits wide, you probably should not
1103 rely on more than 32 bits of payload.
1104 Whether a "signaling" NaN is in any way different from a
1106 "quiet" NaN, depends on the platform. Also note that the
1107 payload of the default NaN (no argument to nan()) is not
1108 necessarily zero, use "setpayload" to explicitly set the
1109 payload. On some platforms like the 32-bit x86, (unless using
1110 the 80-bit long doubles) the signaling bit is not supported at
1111 all.
1112 See also "isnan", "NaN", "setpayload" and "issignaling".
1114 "nearbyint"
1116 Returns the nearest integer to the argument, according to the
1117 current rounding mode (see "fegetround") [C99]. Added in Perl
1118 v5.22.
1119 "nextafter"
1121 Returns the next representable floating point number after "x"
1122 in the direction of "y" [C99]. Added in Perl v5.22.
1123 my $nextafter = POSIX::nextafter($x, $y);
1125 Like "nexttoward", but potentially less accurate.
1127 "nexttoward"
1129 Returns the next representable floating point number after "x"
1130 in the direction of "y" [C99]. Added in Perl v5.22.
1131 my $nexttoward = POSIX::nexttoward($x, $y);
1133 Like "nextafter", but potentially more accurate.
1135 "nice" This is similar to the C function nice(), for changing the
1137 scheduling preference of the current process. Positive
1138 arguments mean a more polite process, negative values a more
1139 needy process. Normal (non-root) user processes can only
1140 change towards being more polite.
1141 Returns "undef" on failure.
1143 "offsetof"
1145 Not implemented. offsetof() is C-specific, you probably want
1146 to see "pack" in perlfunc instead.
1147 "open" Open a file for reading for writing. This returns file
1149 descriptors, not Perl filehandles. Use "POSIX::close" to close
1150 the file.
1151 Open a file read-only with mode 0666.
1153 $fd = POSIX::open( "foo" );
1155 Open a file for read and write.
1157 $fd = POSIX::open( "foo", &POSIX::O_RDWR );
1159 Open a file for write, with truncation.
1161 $fd = POSIX::open(
1163 "foo", &POSIX::O_WRONLY | &POSIX::O_TRUNC
1164 );
1165 Create a new file with mode 0640. Set up the file for writing.
1167 $fd = POSIX::open(
1169 "foo", &POSIX::O_CREAT | &POSIX::O_WRONLY, 0640
1170 );
1171 Returns "undef" on failure.
1173 See also "sysopen" in perlfunc.
1175 "opendir"
1177 Open a directory for reading.
1178 $dir = POSIX::opendir( "/var" );
1180 @files = POSIX::readdir( $dir );
1181 POSIX::closedir( $dir );
1182 Returns "undef" on failure.
1184 "pathconf"
1186 Retrieves the value of a configurable limit on a file or
1187 directory.
1188 The following will determine the maximum length of the longest
1190 allowable pathname on the filesystem which holds "/var".
1191 $path_max = POSIX::pathconf( "/var",
1193 &POSIX::_PC_PATH_MAX );
1194 Returns "undef" on failure.
1196 "pause" This is similar to the C function pause(), which suspends the
1198 execution of the current process until a signal is received.
1199 Returns "undef" on failure.
1201 "perror"
1203 This is identical to the C function perror(), which outputs to
1204 the standard error stream the specified message followed by ":
1205 " and the current error string. Use the warn() function and
1206 the $! variable instead, see "warn" in perlfunc and "$ERRNO"
1207 in perlvar.
1208 "pipe" Create an interprocess channel. This returns file descriptors
1210 like those returned by "POSIX::open".
1211 my ($read, $write) = POSIX::pipe();
1213 POSIX::write( $write, "hello", 5 );
1214 POSIX::read( $read, $buf, 5 );
1215 See also "pipe" in perlfunc.
1217 "pow" Computes $x raised to the power $exponent.
1219 $ret = POSIX::pow( $x, $exponent );
1221 You can also use the "**" operator, see perlop.
1223 "printf"
1225 Formats and prints the specified arguments to "STDOUT". See
1226 also "printf" in perlfunc.
1227 "putc" Not implemented. putc() is C-specific, see "print" in perlfunc
1229 instead.
1230 "putchar"
1232 Not implemented. putchar() is C-specific, see "print" in
1233 perlfunc instead.
1234 "puts" Not implemented. puts() is C-specific, see "print" in perlfunc
1236 instead.
1237 "qsort" Not implemented. qsort() is C-specific, see "sort" in perlfunc
1239 instead.
1240 "raise" Sends the specified signal to the current process. See also
1242 "kill" in perlfunc and the $$ in "$PID" in perlvar.
1243 "rand" Not implemented. rand() is non-portable, see "rand" in
1245 perlfunc instead.
1246 "read" Read from a file. This uses file descriptors such as those
1248 obtained by calling "POSIX::open". If the buffer $buf is not
1249 large enough for the read then Perl will extend it to make room
1250 for the request.
1251 $fd = POSIX::open( "foo", &POSIX::O_RDONLY );
1253 $bytes = POSIX::read( $fd, $buf, 3 );
1254 Returns "undef" on failure.
1256 See also "sysread" in perlfunc.
1258 "readdir"
1260 This is identical to Perl's builtin readdir() function for
1261 reading directory entries, see "readdir" in perlfunc.
1262 "realloc"
1264 Not implemented. realloc() is C-specific. Perl does memory
1265 management transparently.
1266 "remainder"
1268 Given "x" and "y", returns the value "x - n*y", where "n" is
1269 the integer closest to "x"/"y" [C99]. Added in Perl v5.22.
1270 my $remainder = POSIX::remainder($x, $y)
1272 See also "remquo".
1274 "remove"
1276 Deletes a name from the filesystem. Calls "unlink" in perlfunc
1277 for files and "rmdir" in perlfunc for directories.
1278 "remquo"
1280 Like "remainder" but also returns the low-order bits of the
1281 quotient (n) [C99]. Added in Perl v5.22.
1282 (This is quite esoteric interface, mainly used to implement
1284 numerical algorithms.)
1285 "rename"
1287 This is identical to Perl's builtin rename() function for
1288 renaming files, see "rename" in perlfunc.
1289 "rewind"
1291 Seeks to the beginning of the file.
1292 "rewinddir"
1294 This is identical to Perl's builtin rewinddir() function for
1295 rewinding directory entry streams, see "rewinddir" in perlfunc.
1296 "rint" Identical to "lrint".
1298 "rmdir" This is identical to Perl's builtin rmdir() function for
1300 removing (empty) directories, see "rmdir" in perlfunc.
1301 "round" Returns the integer (but still as floating point) nearest to
1303 the argument [C99]. Added in Perl v5.22.
1304 See also "ceil", "floor", "lround", "modf", and "trunc".
1306 "scalbn"
1308 Returns "x * 2**y" [C99]. Added in Perl v5.22.
1309 See also "frexp" and "ldexp".
1311 "scanf" Not implemented. scanf() is C-specific, use <> and regular
1313 expressions instead, see perlre.
1314 "setgid"
1316 Sets the real group identifier and the effective group
1317 identifier for this process. Similar to assigning a value to
1318 the Perl's builtin $) variable, see "$EGID" in perlvar, except
1319 that the latter will change only the real user identifier, and
1320 that the setgid() uses only a single numeric argument, as
1321 opposed to a space-separated list of numbers.
1322 "setjmp"
1324 Not implemented. setjmp() is C-specific: use "eval {}"
1325 instead, see "eval" in perlfunc.
1326 "setlocale"
1328 WARNING! Prior to Perl 5.28 or on a system that does not
1329 support thread-safe locale operations, do NOT use this function
1330 in a thread. The locale will change in all other threads at
1331 the same time, and should your thread get paused by the
1332 operating system, and another started, that thread will not
1333 have the locale it is expecting. On some platforms, there can
1334 be a race leading to segfaults if two threads call this
1335 function nearly simultaneously. This warning does not apply on
1336 unthreaded builds, or on perls where "${^SAFE_LOCALES}" exists
1337 and is non-zero; namely Perl 5.28 and later compiled to be
1338 locale-thread-safe.
1339 This function modifies and queries the program's underlying
1341 locale. Users of this function should read perllocale, whch
1342 provides a comprehensive discussion of Perl locale handling,
1343 knowledge of which is necessary to properly use this function.
1344 It contains a section devoted to this function. The discussion
1345 here is merely a summary reference for setlocale(). Note that
1346 Perl itself is almost entirely unaffected by the locale except
1347 within the scope of "use locale". (Exceptions are listed in
1348 "Not within the scope of "use locale"" in perllocale, and
1349 locale-dependent functions within the POSIX module ARE always
1350 affected by the current locale.)
1351 The following examples assume
1353 use POSIX qw(setlocale LC_ALL LC_CTYPE);
1355 has been issued.
1357 The following will set the traditional UNIX system locale
1359 behavior (the second argument "C").
1360 $loc = setlocale( LC_ALL, "C" );
1362 The following will query the current "LC_CTYPE" category. (No
1364 second argument means 'query'.)
1365 $loc = setlocale( LC_CTYPE );
1367 The following will set the "LC_CTYPE" behaviour according to
1369 the locale environment variables (the second argument "").
1370 Please see your system's setlocale(3) documentation for the
1371 locale environment variables' meaning or consult perllocale.
1372 $loc = setlocale( LC_CTYPE, "" );
1374 The following will set the "LC_COLLATE" behaviour to
1376 Argentinian Spanish. NOTE: The naming and availability of
1377 locales depends on your operating system. Please consult
1378 perllocale for how to find out which locales are available in
1379 your system.
1380 $loc = setlocale( LC_COLLATE, "es_AR.ISO8859-1" );
1382 "setpayload"
1384 use POSIX ':nan_payload';
1385 setpayload($var, $payload);
1386 Sets the "NaN" payload of var. Added in Perl v5.24.
1388 NOTE: the NaN payload APIs are based on the latest (as of June
1390 2015) proposed ISO C interfaces, but they are not yet a
1391 standard. Things may change.
1392 See "nan" for more discussion about "NaN".
1394 See also "setpayloadsig", "isnan", "getpayload", and
1396 "issignaling".
1397 "setpayloadsig"
1399 use POSIX ':nan_payload';
1400 setpayloadsig($var, $payload);
1401 Like "setpayload" but also makes the NaN signaling. Added in
1403 Perl v5.24.
1404 Depending on the platform the NaN may or may not behave
1406 differently.
1407 Note the API instability warning in "setpayload".
1409 Note that because how the floating point formats work out, on
1411 the most common platforms signaling payload of zero is best
1412 avoided, since it might end up being identical to "+Inf".
1413 See also "nan", "isnan", "getpayload", and "issignaling".
1415 "setpgid"
1417 This is similar to the C function setpgid() for setting the
1418 process group identifier of the current process.
1419 Returns "undef" on failure.
1421 "setsid"
1423 This is identical to the C function setsid() for setting the
1424 session identifier of the current process.
1425 "setuid"
1427 Sets the real user identifier and the effective user identifier
1428 for this process. Similar to assigning a value to the Perl's
1429 builtin $< variable, see "$UID" in perlvar, except that the
1430 latter will change only the real user identifier.
1431 "sigaction"
1433 Detailed signal management. This uses "POSIX::SigAction"
1434 objects for the "action" and "oldaction" arguments (the
1435 oldaction can also be just a hash reference). Consult your
1436 system's "sigaction" manpage for details, see also
1437 "POSIX::SigRt".
1438 Synopsis:
1440 sigaction(signal, action, oldaction = 0)
1442 Returns "undef" on failure. The "signal" must be a number
1444 (like "SIGHUP"), not a string (like "SIGHUP"), though Perl does
1445 try hard to understand you.
1446 If you use the "SA_SIGINFO" flag, the signal handler will in
1448 addition to the first argument, the signal name, also receive a
1449 second argument, a hash reference, inside which are the
1450 following keys with the following semantics, as defined by
1451 POSIX/SUSv3:
1452 signo the signal number
1454 errno the error number
1455 code if this is zero or less, the signal was sent by
1456 a user process and the uid and pid make sense,
1457 otherwise the signal was sent by the kernel
1458 The constants for specific "code" values can be imported
1460 individually or using the ":signal_h_si_code" tag, since Perl
1461 v5.24.
1462 The following are also defined by POSIX/SUSv3, but
1464 unfortunately not very widely implemented:
1465 pid the process id generating the signal
1467 uid the uid of the process id generating the signal
1468 status exit value or signal for SIGCHLD
1469 band band event for SIGPOLL
1470 addr address of faulting instruction or memory
1471 reference for SIGILL, SIGFPE, SIGSEGV or SIGBUS
1472 A third argument is also passed to the handler, which contains
1474 a copy of the raw binary contents of the "siginfo" structure:
1475 if a system has some non-POSIX fields, this third argument is
1476 where to unpack() them from.
1477 Note that not all "siginfo" values make sense simultaneously
1479 (some are valid only for certain signals, for example), and not
1480 all values make sense from Perl perspective, you should to
1481 consult your system's "sigaction" and possibly also "siginfo"
1482 documentation.
1483 "siglongjmp"
1485 Not implemented. siglongjmp() is C-specific: use "die" in
1486 perlfunc instead.
1487 "signbit"
1489 Returns zero for positive arguments, non-zero for negative
1490 arguments [C99]. Added in Perl v5.22.
1491 "sigpending"
1493 Examine signals that are blocked and pending. This uses
1494 "POSIX::SigSet" objects for the "sigset" argument. Consult
1495 your system's "sigpending" manpage for details.
1496 Synopsis:
1498 sigpending(sigset)
1500 Returns "undef" on failure.
1502 "sigprocmask"
1504 Change and/or examine calling process's signal mask. This uses
1505 "POSIX::SigSet" objects for the "sigset" and "oldsigset"
1506 arguments. Consult your system's "sigprocmask" manpage for
1507 details.
1508 Synopsis:
1510 sigprocmask(how, sigset, oldsigset = 0)
1512 Returns "undef" on failure.
1514 Note that you can't reliably block or unblock a signal from its
1516 own signal handler if you're using safe signals. Other signals
1517 can be blocked or unblocked reliably.
1518 "sigsetjmp"
1520 Not implemented. sigsetjmp() is C-specific: use "eval {}"
1521 instead, see "eval" in perlfunc.
1522 "sigsuspend"
1524 Install a signal mask and suspend process until signal arrives.
1525 This uses "POSIX::SigSet" objects for the "signal_mask"
1526 argument. Consult your system's "sigsuspend" manpage for
1527 details.
1528 Synopsis:
1530 sigsuspend(signal_mask)
1532 Returns "undef" on failure.
1534 "sin" This is identical to Perl's builtin sin() function for
1536 returning the sine of the numerical argument, see "sin" in
1537 perlfunc. See also Math::Trig.
1538 "sinh" This is identical to the C function sinh() for returning the
1540 hyperbolic sine of the numerical argument. See also
1541 Math::Trig.
1542 "sleep" This is functionally identical to Perl's builtin sleep()
1544 function for suspending the execution of the current for
1545 process for certain number of seconds, see "sleep" in perlfunc.
1546 There is one significant difference, however: POSIX::sleep()
1547 returns the number of unslept seconds, while the CORE::sleep()
1548 returns the number of slept seconds.
1549 "sprintf"
1551 This is similar to Perl's builtin sprintf() function for
1552 returning a string that has the arguments formatted as
1553 requested, see "sprintf" in perlfunc.
1554 "sqrt" This is identical to Perl's builtin sqrt() function. for
1556 returning the square root of the numerical argument, see "sqrt"
1557 in perlfunc.
1558 "srand" Give a seed the pseudorandom number generator, see "srand" in
1560 perlfunc.
1561 "sscanf"
1563 Not implemented. sscanf() is C-specific, use regular
1564 expressions instead, see perlre.
1565 "stat" This is identical to Perl's builtin stat() function for
1567 returning information about files and directories.
1568 "strcat"
1570 Not implemented. strcat() is C-specific, use ".=" instead, see
1571 perlop.
1572 "strchr"
1574 Not implemented. strchr() is C-specific, see "index" in
1575 perlfunc instead.
1576 "strcmp"
1578 Not implemented. strcmp() is C-specific, use "eq" or "cmp"
1579 instead, see perlop.
1580 "strcoll"
1582 This is identical to the C function strcoll() for collating
1583 (comparing) strings transformed using the strxfrm() function.
1584 Not really needed since Perl can do this transparently, see
1585 perllocale.
1586 Beware that in a UTF-8 locale, anything you pass to this
1588 function must be in UTF-8; and when not in a UTF-8 locale,
1589 anything passed must not be UTF-8 encoded.
1590 Note also that it doesn't make sense for a string to be encoded
1592 in one locale (say, ISO-8859-6, Arabic) and to collate it based
1593 on another (like ISO-8859-7, Greek). The results will be
1594 essentially meaningless.
1595 "strcpy"
1597 Not implemented. strcpy() is C-specific, use "=" instead, see
1598 perlop.
1599 "strcspn"
1601 Not implemented. strcspn() is C-specific, use regular
1602 expressions instead, see perlre.
1603 "strerror"
1605 Returns the error string for the specified errno. Identical to
1606 the string form of $!, see "$ERRNO" in perlvar.
1607 "strftime"
1609 Convert date and time information to string. Returns the
1610 string.
1611 Synopsis:
1613 strftime(fmt, sec, min, hour, mday, mon, year,
1615 wday = -1, yday = -1, isdst = -1)
1616 The month ("mon"), weekday ("wday"), and yearday ("yday") begin
1618 at zero, i.e., January is 0, not 1; Sunday is 0, not 1; January
1619 1st is 0, not 1. The year ("year") is given in years since
1620 1900, i.e., the year 1995 is 95; the year 2001 is 101. Consult
1621 your system's strftime() manpage for details about these and
1622 the other arguments.
1623 If you want your code to be portable, your format ("fmt")
1625 argument should use only the conversion specifiers defined by
1626 the ANSI C standard (C99, to play safe). These are
1627 "aAbBcdHIjmMpSUwWxXyYZ%". But even then, the results of some
1628 of the conversion specifiers are non-portable. For example,
1629 the specifiers "aAbBcpZ" change according to the locale
1630 settings of the user, and both how to set locales (the locale
1631 names) and what output to expect are non-standard. The
1632 specifier "c" changes according to the timezone settings of the
1633 user and the timezone computation rules of the operating
1634 system. The "Z" specifier is notoriously unportable since the
1635 names of timezones are non-standard. Sticking to the numeric
1636 specifiers is the safest route.
1637 The given arguments are made consistent as though by calling
1639 mktime() before calling your system's strftime() function,
1640 except that the "isdst" value is not affected.
1641 The string for Tuesday, December 12, 1995.
1643 $str = POSIX::strftime( "%A, %B %d, %Y",
1645 0, 0, 0, 12, 11, 95, 2 );
1646 print "$str\n";
1647 "strlen"
1649 Not implemented. strlen() is C-specific, use length() instead,
1650 see "length" in perlfunc.
1651 "strncat"
1653 Not implemented. strncat() is C-specific, use ".=" instead,
1654 see perlop.
1655 "strncmp"
1657 Not implemented. strncmp() is C-specific, use "eq" instead,
1658 see perlop.
1659 "strncpy"
1661 Not implemented. strncpy() is C-specific, use "=" instead, see
1662 perlop.
1663 "strpbrk"
1665 Not implemented. strpbrk() is C-specific, use regular
1666 expressions instead, see perlre.
1667 "strrchr"
1669 Not implemented. strrchr() is C-specific, see "rindex" in
1670 perlfunc instead.
1671 "strspn"
1673 Not implemented. strspn() is C-specific, use regular
1674 expressions instead, see perlre.
1675 "strstr"
1677 This is identical to Perl's builtin index() function, see
1678 "index" in perlfunc.
1679 "strtod"
1681 String to double translation. Returns the parsed number and the
1682 number of characters in the unparsed portion of the string.
1683 Truly POSIX-compliant systems set $! ($ERRNO) to indicate a
1684 translation error, so clear $! before calling "strtod".
1685 However, non-POSIX systems may not check for overflow, and
1686 therefore will never set $!.
1687 "strtod" respects any POSIX setlocale() "LC_NUMERIC" settings,
1689 regardless of whether or not it is called from Perl code that
1690 is within the scope of "use locale". Prior to Perl 5.28, or
1691 when operating in a non thread-safe environment, it should not
1692 be used in a threaded application unless it's certain that the
1693 underlying locale is C or POSIX. This is because it otherwise
1694 changes the locale, which globally affects all threads
1695 simultaneously.
1696 To parse a string $str as a floating point number use
1698 $! = 0;
1700 ($num, $n_unparsed) = POSIX::strtod($str);
1701 The second returned item and $! can be used to check for valid
1703 input:
1704 if (($str eq '') || ($n_unparsed != 0) || $!) {
1706 die "Non-numeric input $str" . ($! ? ": $!\n" : "\n");
1707 }
1708 When called in a scalar context "strtod" returns the parsed
1710 number.
1711 "strtok"
1713 Not implemented. strtok() is C-specific, use regular
1714 expressions instead, see perlre, or "split" in perlfunc.
1715 "strtol"
1717 String to (long) integer translation. Returns the parsed
1718 number and the number of characters in the unparsed portion of
1719 the string. Truly POSIX-compliant systems set $! ($ERRNO) to
1720 indicate a translation error, so clear $! before calling
1721 "strtol". However, non-POSIX systems may not check for
1722 overflow, and therefore will never set $!.
1723 "strtol" should respect any POSIX setlocale() settings.
1725 To parse a string $str as a number in some base $base use
1727 $! = 0;
1729 ($num, $n_unparsed) = POSIX::strtol($str, $base);
1730 The base should be zero or between 2 and 36, inclusive. When
1732 the base is zero or omitted "strtol" will use the string itself
1733 to determine the base: a leading "0x" or "0X" means
1734 hexadecimal; a leading "0" means octal; any other leading
1735 characters mean decimal. Thus, "1234" is parsed as a decimal
1736 number, "01234" as an octal number, and "0x1234" as a
1737 hexadecimal number.
1738 The second returned item and $! can be used to check for valid
1740 input:
1741 if (($str eq '') || ($n_unparsed != 0) || !$!) {
1743 die "Non-numeric input $str" . $! ? ": $!\n" : "\n";
1744 }
1745 When called in a scalar context "strtol" returns the parsed
1747 number.
1748 "strtold"
1750 Like "strtod" but for long doubles. Defined only if the system
1751 supports long doubles.
1752 "strtoul"
1754 String to unsigned (long) integer translation. strtoul() is
1755 identical to strtol() except that strtoul() only parses
1756 unsigned integers. See "strtol" for details.
1757 Note: Some vendors supply strtod() and strtol() but not
1759 strtoul(). Other vendors that do supply strtoul() parse "-1"
1760 as a valid value.
1761 "strxfrm"
1763 String transformation. Returns the transformed string.
1764 $dst = POSIX::strxfrm( $src );
1766 Used with "eq" or "cmp" as an alternative to "strcoll".
1768 Not really needed since Perl can do this transparently, see
1770 perllocale.
1771 Unlike the libc "strxfrm", this allows NUL characters in the
1773 input $src.
1774 It doesn't make sense for a string to be encoded in one locale
1776 (say, ISO-8859-6, Arabic) and to collate it based on another
1777 (like ISO-8859-7, Greek). Perl assumes that the current
1778 "LC_CTYPE" locale correctly represents the encoding of $src,
1779 and ignores the value of "LC_COLLATE".
1780 "sysconf"
1782 Retrieves values of system configurable variables.
1783 The following will get the machine's clock speed.
1785 $clock_ticks = POSIX::sysconf( &POSIX::_SC_CLK_TCK );
1787 Returns "undef" on failure.
1789 "system"
1791 This is identical to Perl's builtin system() function, see
1792 "system" in perlfunc.
1793 "tan" This is identical to the C function tan(), returning the
1795 tangent of the numerical argument. See also Math::Trig.
1796 "tanh" This is identical to the C function tanh(), returning the
1798 hyperbolic tangent of the numerical argument. See also
1799 Math::Trig.
1800 "tcdrain"
1802 This is similar to the C function tcdrain() for draining the
1803 output queue of its argument stream.
1804 Returns "undef" on failure.
1806 "tcflow"
1808 This is similar to the C function tcflow() for controlling the
1809 flow of its argument stream.
1810 Returns "undef" on failure.
1812 "tcflush"
1814 This is similar to the C function tcflush() for flushing the
1815 I/O buffers of its argument stream.
1816 Returns "undef" on failure.
1818 "tcgetpgrp"
1820 This is identical to the C function tcgetpgrp() for returning
1821 the process group identifier of the foreground process group of
1822 the controlling terminal.
1823 "tcsendbreak"
1825 This is similar to the C function tcsendbreak() for sending a
1826 break on its argument stream.
1827 Returns "undef" on failure.
1829 "tcsetpgrp"
1831 This is similar to the C function tcsetpgrp() for setting the
1832 process group identifier of the foreground process group of the
1833 controlling terminal.
1834 Returns "undef" on failure.
1836 "tgamma"
1838 The Gamma function [C99]. Added in Perl v5.22.
1839 See also "lgamma".
1841 "time" This is identical to Perl's builtin time() function for
1843 returning the number of seconds since the epoch (whatever it is
1844 for the system), see "time" in perlfunc.
1845 "times" The times() function returns elapsed realtime since some point
1847 in the past (such as system startup), user and system times for
1848 this process, and user and system times used by child
1849 processes. All times are returned in clock ticks.
1850 ($realtime, $user, $system, $cuser, $csystem)
1852 = POSIX::times();
1853 Note: Perl's builtin times() function returns four values,
1855 measured in seconds.
1856 "tmpfile"
1858 Not implemented. Use method IO::File::new_tmpfile() instead,
1859 or see File::Temp.
1860 "tmpnam"
1862 For security reasons, which are probably detailed in your
1863 system's documentation for the C library tmpnam() function,
1864 this interface is no longer available since Perl v5.26; instead
1865 use File::Temp.
1866 "tolower"
1868 This function has been removed as of Perl v5.26. This is
1869 identical to the C function, except that it can apply to a
1870 single character or to a whole string, and currently operates
1871 as if the locale always is "C". Consider using the lc()
1872 function, see "lc" in perlfunc, see "lc" in perlfunc, or the
1873 equivalent "\L" operator inside doublequotish strings.
1874 "toupper"
1876 This function has been removed as of Perl v5.26. This is
1877 similar to the C function, except that it can apply to a single
1878 character or to a whole string, and currently operates as if
1879 the locale always is "C". Consider using the uc() function,
1880 see "uc" in perlfunc, or the equivalent "\U" operator inside
1881 doublequotish strings.
1882 "trunc" Returns the integer toward zero from the argument [C99]. Added
1884 in Perl v5.22.
1885 See also "ceil", "floor", and "round".
1887 "ttyname"
1889 This is identical to the C function ttyname() for returning the
1890 name of the current terminal.
1891 "tzname"
1893 Retrieves the time conversion information from the "tzname"
1894 variable.
1895 POSIX::tzset();
1897 ($std, $dst) = POSIX::tzname();
1898 "tzset" This is identical to the C function tzset() for setting the
1900 current timezone based on the environment variable "TZ", to be
1901 used by ctime(), localtime(), mktime(), and strftime()
1902 functions.
1903 "umask" This is identical to Perl's builtin umask() function for
1905 setting (and querying) the file creation permission mask, see
1906 "umask" in perlfunc.
1907 "uname" Get name of current operating system.
1909 ($sysname, $nodename, $release, $version, $machine)
1911 = POSIX::uname();
1912 Note that the actual meanings of the various fields are not
1914 that well standardized, do not expect any great portability.
1915 The $sysname might be the name of the operating system, the
1916 $nodename might be the name of the host, the $release might be
1917 the (major) release number of the operating system, the
1918 $version might be the (minor) release number of the operating
1919 system, and the $machine might be a hardware identifier.
1920 Maybe.
1921 "ungetc"
1923 Not implemented. Use method IO::Handle::ungetc() instead.
1924 "unlink"
1926 This is identical to Perl's builtin unlink() function for
1927 removing files, see "unlink" in perlfunc.
1928 "utime" This is identical to Perl's builtin utime() function for
1930 changing the time stamps of files and directories, see "utime"
1931 in perlfunc.
1932 "vfprintf"
1934 Not implemented. vfprintf() is C-specific, see "printf" in
1935 perlfunc instead.
1936 "vprintf"
1938 Not implemented. vprintf() is C-specific, see "printf" in
1939 perlfunc instead.
1940 "vsprintf"
1942 Not implemented. vsprintf() is C-specific, see "sprintf" in
1943 perlfunc instead.
1944 "wait" This is identical to Perl's builtin wait() function, see "wait"
1946 in perlfunc.
1947 "waitpid"
1949 Wait for a child process to change state. This is identical to
1950 Perl's builtin waitpid() function, see "waitpid" in perlfunc.
1951 $pid = POSIX::waitpid( -1, POSIX::WNOHANG );
1953 print "status = ", ($? / 256), "\n";
1954 See "mblen".
1956 "wctomb"
1958 This is the same as the C function wctomb() on unthreaded
1959 perls. On threaded perls, it transparently (almost)
1960 substitutes the more thread-safe "wcrtomb"(3), if available,
1961 instead of "wctomb".
1962 Core Perl does not have any support for wide and multibyte
1964 locales, except Unicode UTF-8 locales. This function, in
1965 conjunction with "mblen" and "mbtowc" may be used to roll your
1966 own decoding/encoding of other types of multi-byte locales.
1967 Use "undef" as the first parameter to this function to get the
1969 effect of passing NULL as the first parameter to "wctomb".
1970 This ignores the second parameter, and resets any shift state
1971 to its initial value. The return value is undefined if
1972 "wcrtomb" was substituted, so you should never rely on it.
1973 When the first parameter is a scalar, the code point contained
1975 in the scalar second parameter is converted into a multi-byte
1976 string and stored into the first parameter scalar. This is
1977 based on the locale that currently underlies the program,
1978 regardless of whether or not the function is called from Perl
1979 code that is within the scope of "use locale". The return
1980 value is the number of bytes stored; or negative if the code
1981 point isn't representable in the current locale. Perl makes no
1982 attempt at hiding from your code any differences in the "errno"
1983 setting between "wctomb" and "wcrtomb". It does set "errno" to
1984 0 before calling them.
1985 "write" Write to a file. This uses file descriptors such as those
1987 obtained by calling "POSIX::open".
1988 $fd = POSIX::open( "foo", &POSIX::O_WRONLY );
1990 $buf = "hello";
1991 $bytes = POSIX::write( $fd, $buf, 5 );
1992 Returns "undef" on failure.
1994 See also "syswrite" in perlfunc.
1996
1998 "POSIX::SigAction"
1999 "new" Creates a new "POSIX::SigAction" object which corresponds to
2000 the C "struct sigaction". This object will be destroyed
2001 automatically when it is no longer needed. The first parameter
2002 is the handler, a sub reference. The second parameter is a
2003 "POSIX::SigSet" object, it defaults to the empty set. The
2004 third parameter contains the "sa_flags", it defaults to 0.
2005 $sigset = POSIX::SigSet->new(SIGINT, SIGQUIT);
2007 $sigaction = POSIX::SigAction->new(
2008 \&handler, $sigset, &POSIX::SA_NOCLDSTOP
2009 );
2010 This "POSIX::SigAction" object is intended for use with the
2012 POSIX::sigaction() function.
2013 "handler"
2015 "mask"
2016 "flags" accessor functions to get/set the values of a SigAction object.
2017 $sigset = $sigaction->mask;
2019 $sigaction->flags(&POSIX::SA_RESTART);
2020 "safe" accessor function for the "safe signals" flag of a SigAction
2022 object; see perlipc for general information on safe (a.k.a.
2023 "deferred") signals. If you wish to handle a signal safely,
2024 use this accessor to set the "safe" flag in the
2025 "POSIX::SigAction" object:
2026 $sigaction->safe(1);
2028 You may also examine the "safe" flag on the output action
2030 object which is filled in when given as the third parameter to
2031 POSIX::sigaction():
2032 sigaction(SIGINT, $new_action, $old_action);
2034 if ($old_action->safe) {
2035 # previous SIGINT handler used safe signals
2036 }
2037 "POSIX::SigRt"
2039 %SIGRT A hash of the POSIX realtime signal handlers. It is an
2040 extension of the standard %SIG, the $POSIX::SIGRT{SIGRTMIN} is
2041 roughly equivalent to $SIG{SIGRTMIN}, but the right POSIX moves
2042 (see below) are made with the "POSIX::SigSet" and
2043 "POSIX::sigaction" instead of accessing the %SIG.
2044 You can set the %POSIX::SIGRT elements to set the POSIX
2046 realtime signal handlers, use "delete" and "exists" on the
2047 elements, and use "scalar" on the %POSIX::SIGRT to find out how
2048 many POSIX realtime signals there are available
2049 "(SIGRTMAX - SIGRTMIN + 1", the "SIGRTMAX" is a valid POSIX
2050 realtime signal).
2051 Setting the %SIGRT elements is equivalent to calling this:
2053 sub new {
2055 my ($rtsig, $handler, $flags) = @_;
2056 my $sigset = POSIX::SigSet($rtsig);
2057 my $sigact = POSIX::SigAction->new($handler,$sigset,$flags);
2058 sigaction($rtsig, $sigact);
2059 }
2060 The flags default to zero, if you want something different you
2062 can either use "local" on $POSIX::SigRt::SIGACTION_FLAGS, or
2063 you can derive from POSIX::SigRt and define your own new() (the
2064 tied hash STORE method of the %SIGRT calls "new($rtsig,
2065 $handler, $SIGACTION_FLAGS)", where the $rtsig ranges from zero
2066 to "SIGRTMAX - SIGRTMIN + 1)".
2067 Just as with any signal, you can use "sigaction($rtsig, undef,
2069 $oa)" to retrieve the installed signal handler (or, rather, the
2070 signal action).
2071 NOTE: whether POSIX realtime signals really work in your
2073 system, or whether Perl has been compiled so that it works with
2074 them, is outside of this discussion.
2075 "SIGRTMIN"
2077 Return the minimum POSIX realtime signal number available, or
2078 "undef" if no POSIX realtime signals are available.
2079 "SIGRTMAX"
2081 Return the maximum POSIX realtime signal number available, or
2082 "undef" if no POSIX realtime signals are available.
2083 "POSIX::SigSet"
2085 "new" Create a new SigSet object. This object will be destroyed
2086 automatically when it is no longer needed. Arguments may be
2087 supplied to initialize the set.
2088 Create an empty set.
2090 $sigset = POSIX::SigSet->new;
2092 Create a set with "SIGUSR1".
2094 $sigset = POSIX::SigSet->new( &POSIX::SIGUSR1 );
2096 Throws an error if any of the signals supplied cannot be added
2098 to the set.
2099 "addset"
2101 Add a signal to a SigSet object.
2102 $sigset->addset( &POSIX::SIGUSR2 );
2104 Returns "undef" on failure.
2106 "delset"
2108 Remove a signal from the SigSet object.
2109 $sigset->delset( &POSIX::SIGUSR2 );
2111 Returns "undef" on failure.
2113 "emptyset"
2115 Initialize the SigSet object to be empty.
2116 $sigset->emptyset();
2118 Returns "undef" on failure.
2120 "fillset"
2122 Initialize the SigSet object to include all signals.
2123 $sigset->fillset();
2125 Returns "undef" on failure.
2127 "ismember"
2129 Tests the SigSet object to see if it contains a specific
2130 signal.
2131 if( $sigset->ismember( &POSIX::SIGUSR1 ) ){
2133 print "contains SIGUSR1\n";
2134 }
2135 "POSIX::Termios"
2137 "new" Create a new Termios object. This object will be destroyed
2138 automatically when it is no longer needed. A Termios object
2139 corresponds to the "termios" C struct. new() mallocs a new
2140 one, getattr() fills it from a file descriptor, and setattr()
2141 sets a file descriptor's parameters to match Termios' contents.
2142 $termios = POSIX::Termios->new;
2144 "getattr"
2146 Get terminal control attributes.
2147 Obtain the attributes for "stdin".
2149 $termios->getattr( 0 ) # Recommended for clarity.
2151 $termios->getattr()
2152 Obtain the attributes for stdout.
2154 $termios->getattr( 1 )
2156 Returns "undef" on failure.
2158 "getcc" Retrieve a value from the "c_cc" field of a "termios" object.
2160 The "c_cc" field is an array so an index must be specified.
2161 $c_cc[1] = $termios->getcc(1);
2163 "getcflag"
2165 Retrieve the "c_cflag" field of a "termios" object.
2166 $c_cflag = $termios->getcflag;
2168 "getiflag"
2170 Retrieve the "c_iflag" field of a "termios" object.
2171 $c_iflag = $termios->getiflag;
2173 "getispeed"
2175 Retrieve the input baud rate.
2176 $ispeed = $termios->getispeed;
2178 "getlflag"
2180 Retrieve the "c_lflag" field of a "termios" object.
2181 $c_lflag = $termios->getlflag;
2183 "getoflag"
2185 Retrieve the "c_oflag" field of a "termios" object.
2186 $c_oflag = $termios->getoflag;
2188 "getospeed"
2190 Retrieve the output baud rate.
2191 $ospeed = $termios->getospeed;
2193 "setattr"
2195 Set terminal control attributes.
2196 Set attributes immediately for stdout.
2198 $termios->setattr( 1, &POSIX::TCSANOW );
2200 Returns "undef" on failure.
2202 "setcc" Set a value in the "c_cc" field of a "termios" object. The
2204 "c_cc" field is an array so an index must be specified.
2205 $termios->setcc( &POSIX::VEOF, 1 );
2207 "setcflag"
2209 Set the "c_cflag" field of a "termios" object.
2210 $termios->setcflag( $c_cflag | &POSIX::CLOCAL );
2212 "setiflag"
2214 Set the "c_iflag" field of a "termios" object.
2215 $termios->setiflag( $c_iflag | &POSIX::BRKINT );
2217 "setispeed"
2219 Set the input baud rate.
2220 $termios->setispeed( &POSIX::B9600 );
2222 Returns "undef" on failure.
2224 "setlflag"
2226 Set the "c_lflag" field of a "termios" object.
2227 $termios->setlflag( $c_lflag | &POSIX::ECHO );
2229 "setoflag"
2231 Set the "c_oflag" field of a "termios" object.
2232 $termios->setoflag( $c_oflag | &POSIX::OPOST );
2234 "setospeed"
2236 Set the output baud rate.
2237 $termios->setospeed( &POSIX::B9600 );
2239 Returns "undef" on failure.
2241 Baud rate values
2243 "B38400" "B75" "B200" "B134" "B300" "B1800" "B150" "B0"
2244 "B19200" "B1200" "B9600" "B600" "B4800" "B50" "B2400" "B110"
2245 Terminal interface values
2247 "TCSADRAIN" "TCSANOW" "TCOON" "TCIOFLUSH" "TCOFLUSH" "TCION"
2248 "TCIFLUSH" "TCSAFLUSH" "TCIOFF" "TCOOFF"
2249 "c_cc" field values
2251 "VEOF" "VEOL" "VERASE" "VINTR" "VKILL" "VQUIT" "VSUSP" "VSTART"
2252 "VSTOP" "VMIN" "VTIME" "NCCS"
2253 "c_cflag" field values
2255 "CLOCAL" "CREAD" "CSIZE" "CS5" "CS6" "CS7" "CS8" "CSTOPB"
2256 "HUPCL" "PARENB" "PARODD"
2257 "c_iflag" field values
2259 "BRKINT" "ICRNL" "IGNBRK" "IGNCR" "IGNPAR" "INLCR" "INPCK"
2260 "ISTRIP" "IXOFF" "IXON" "PARMRK"
2261 "c_lflag" field values
2263 "ECHO" "ECHOE" "ECHOK" "ECHONL" "ICANON" "IEXTEN" "ISIG"
2264 "NOFLSH" "TOSTOP"
2265 "c_oflag" field values
2267 "OPOST"
2268
2270 Constants
2271 "_PC_CHOWN_RESTRICTED" "_PC_LINK_MAX" "_PC_MAX_CANON"
2272 "_PC_MAX_INPUT" "_PC_NAME_MAX" "_PC_NO_TRUNC" "_PC_PATH_MAX"
2273 "_PC_PIPE_BUF" "_PC_VDISABLE"
2274
2276 Constants
2277 "_POSIX_ARG_MAX" "_POSIX_CHILD_MAX" "_POSIX_CHOWN_RESTRICTED"
2278 "_POSIX_JOB_CONTROL" "_POSIX_LINK_MAX" "_POSIX_MAX_CANON"
2279 "_POSIX_MAX_INPUT" "_POSIX_NAME_MAX" "_POSIX_NGROUPS_MAX"
2280 "_POSIX_NO_TRUNC" "_POSIX_OPEN_MAX" "_POSIX_PATH_MAX"
2281 "_POSIX_PIPE_BUF" "_POSIX_SAVED_IDS" "_POSIX_SSIZE_MAX"
2282 "_POSIX_STREAM_MAX" "_POSIX_TZNAME_MAX" "_POSIX_VDISABLE"
2283 "_POSIX_VERSION"
2284
2286 Imported with the ":sys_resource_h" tag.
2287 Constants
2289 Added in Perl v5.28:
2290 "PRIO_PROCESS" "PRIO_PGRP" "PRIO_USER"
2292
2294 Constants
2295 "_SC_ARG_MAX" "_SC_CHILD_MAX" "_SC_CLK_TCK" "_SC_JOB_CONTROL"
2296 "_SC_NGROUPS_MAX" "_SC_OPEN_MAX" "_SC_PAGESIZE" "_SC_SAVED_IDS"
2297 "_SC_STREAM_MAX" "_SC_TZNAME_MAX" "_SC_VERSION"
2298
2300 Constants
2301 "E2BIG" "EACCES" "EADDRINUSE" "EADDRNOTAVAIL" "EAFNOSUPPORT"
2302 "EAGAIN" "EALREADY" "EBADF" "EBADMSG" "EBUSY" "ECANCELED"
2303 "ECHILD" "ECONNABORTED" "ECONNREFUSED" "ECONNRESET" "EDEADLK"
2304 "EDESTADDRREQ" "EDOM" "EDQUOT" "EEXIST" "EFAULT" "EFBIG"
2305 "EHOSTDOWN" "EHOSTUNREACH" "EIDRM" "EILSEQ" "EINPROGRESS"
2306 "EINTR" "EINVAL" "EIO" "EISCONN" "EISDIR" "ELOOP" "EMFILE"
2307 "EMLINK" "EMSGSIZE" "ENAMETOOLONG" "ENETDOWN" "ENETRESET"
2308 "ENETUNREACH" "ENFILE" "ENOBUFS" "ENODATA" "ENODEV" "ENOENT"
2309 "ENOEXEC" "ENOLCK" "ENOLINK" "ENOMEM" "ENOMSG" "ENOPROTOOPT"
2310 "ENOSPC" "ENOSR" "ENOSTR" "ENOSYS" "ENOTBLK" "ENOTCONN"
2311 "ENOTDIR" "ENOTEMPTY" "ENOTRECOVERABLE" "ENOTSOCK" "ENOTSUP"
2312 "ENOTTY" "ENXIO" "EOPNOTSUPP" "EOTHER" "EOVERFLOW" "EOWNERDEAD"
2313 "EPERM" "EPFNOSUPPORT" "EPIPE" "EPROCLIM" "EPROTO"
2314 "EPROTONOSUPPORT" "EPROTOTYPE" "ERANGE" "EREMOTE" "ERESTART"
2315 "EROFS" "ESHUTDOWN" "ESOCKTNOSUPPORT" "ESPIPE" "ESRCH" "ESTALE"
2316 "ETIME" "ETIMEDOUT" "ETOOMANYREFS" "ETXTBSY" "EUSERS"
2317 "EWOULDBLOCK" "EXDEV"
2318
2320 Constants
2321 "FD_CLOEXEC" "F_DUPFD" "F_GETFD" "F_GETFL" "F_GETLK" "F_OK"
2322 "F_RDLCK" "F_SETFD" "F_SETFL" "F_SETLK" "F_SETLKW" "F_UNLCK"
2323 "F_WRLCK" "O_ACCMODE" "O_APPEND" "O_CREAT" "O_EXCL" "O_NOCTTY"
2324 "O_NONBLOCK" "O_RDONLY" "O_RDWR" "O_TRUNC" "O_WRONLY"
2325
2327 Constants
2328 "DBL_DIG" "DBL_EPSILON" "DBL_MANT_DIG" "DBL_MAX"
2329 "DBL_MAX_10_EXP" "DBL_MAX_EXP" "DBL_MIN" "DBL_MIN_10_EXP"
2330 "DBL_MIN_EXP" "FLT_DIG" "FLT_EPSILON" "FLT_MANT_DIG" "FLT_MAX"
2331 "FLT_MAX_10_EXP" "FLT_MAX_EXP" "FLT_MIN" "FLT_MIN_10_EXP"
2332 "FLT_MIN_EXP" "FLT_RADIX" "FLT_ROUNDS" "LDBL_DIG"
2333 "LDBL_EPSILON" "LDBL_MANT_DIG" "LDBL_MAX" "LDBL_MAX_10_EXP"
2334 "LDBL_MAX_EXP" "LDBL_MIN" "LDBL_MIN_10_EXP" "LDBL_MIN_EXP"
2335
2337 Constants
2338 "FE_DOWNWARD" "FE_TONEAREST" "FE_TOWARDZERO" "FE_UPWARD" on
2339 systems that support them.
2340
2342 Constants
2343 "ARG_MAX" "CHAR_BIT" "CHAR_MAX" "CHAR_MIN" "CHILD_MAX"
2344 "INT_MAX" "INT_MIN" "LINK_MAX" "LONG_MAX" "LONG_MIN"
2345 "MAX_CANON" "MAX_INPUT" "MB_LEN_MAX" "NAME_MAX" "NGROUPS_MAX"
2346 "OPEN_MAX" "PATH_MAX" "PIPE_BUF" "SCHAR_MAX" "SCHAR_MIN"
2347 "SHRT_MAX" "SHRT_MIN" "SSIZE_MAX" "STREAM_MAX" "TZNAME_MAX"
2348 "UCHAR_MAX" "UINT_MAX" "ULONG_MAX" "USHRT_MAX"
2349
2351 Constants
2352 "LC_ALL" "LC_COLLATE" "LC_CTYPE" "LC_MONETARY" "LC_NUMERIC"
2353 "LC_TIME" "LC_MESSAGES" on systems that support them.
2354
2356 Constants
2357 "HUGE_VAL"
2358 Added in Perl v5.22:
2360 "FP_ILOGB0" "FP_ILOGBNAN" "FP_INFINITE" "FP_NAN" "FP_NORMAL"
2362 "FP_SUBNORMAL" "FP_ZERO" "INFINITY" "NAN" "Inf" "NaN" "M_1_PI"
2363 "M_2_PI" "M_2_SQRTPI" "M_E" "M_LN10" "M_LN2" "M_LOG10E"
2364 "M_LOG2E" "M_PI" "M_PI_2" "M_PI_4" "M_SQRT1_2" "M_SQRT2" on
2365 systems with C99 support.
2366
2368 Constants
2369 "SA_NOCLDSTOP" "SA_NOCLDWAIT" "SA_NODEFER" "SA_ONSTACK"
2370 "SA_RESETHAND" "SA_RESTART" "SA_SIGINFO" "SIGABRT" "SIGALRM"
2371 "SIGCHLD" "SIGCONT" "SIGFPE" "SIGHUP" "SIGILL" "SIGINT"
2372 "SIGKILL" "SIGPIPE" "SIGQUIT" "SIGSEGV" "SIGSTOP" "SIGTERM"
2373 "SIGTSTP" "SIGTTIN" "SIGTTOU" "SIGUSR1" "SIGUSR2" "SIG_BLOCK"
2374 "SIG_DFL" "SIG_ERR" "SIG_IGN" "SIG_SETMASK" "SIG_UNBLOCK"
2375 Added in Perl v5.24:
2377 "ILL_ILLOPC" "ILL_ILLOPN" "ILL_ILLADR" "ILL_ILLTRP"
2379 "ILL_PRVOPC" "ILL_PRVREG" "ILL_COPROC" "ILL_BADSTK"
2380 "FPE_INTDIV" "FPE_INTOVF" "FPE_FLTDIV" "FPE_FLTOVF"
2381 "FPE_FLTUND" "FPE_FLTRES" "FPE_FLTINV" "FPE_FLTSUB"
2382 "SEGV_MAPERR" "SEGV_ACCERR" "BUS_ADRALN" "BUS_ADRERR"
2383 "BUS_OBJERR" "TRAP_BRKPT" "TRAP_TRACE" "CLD_EXITED"
2384 "CLD_KILLED" "CLD_DUMPED" "CLD_TRAPPED" "CLD_STOPPED"
2385 "CLD_CONTINUED" "POLL_IN" "POLL_OUT" "POLL_MSG" "POLL_ERR"
2386 "POLL_PRI" "POLL_HUP" "SI_USER" "SI_QUEUE" "SI_TIMER"
2387 "SI_ASYNCIO" "SI_MESGQ"
2388
2390 Constants
2391 "S_IRGRP" "S_IROTH" "S_IRUSR" "S_IRWXG" "S_IRWXO" "S_IRWXU"
2392 "S_ISGID" "S_ISUID" "S_IWGRP" "S_IWOTH" "S_IWUSR" "S_IXGRP"
2393 "S_IXOTH" "S_IXUSR"
2394 Macros "S_ISBLK" "S_ISCHR" "S_ISDIR" "S_ISFIFO" "S_ISLNK" "S_ISREG"
2396 "S_ISSOCK"
2397
2399 Constants
2400 "EXIT_FAILURE" "EXIT_SUCCESS" "MB_CUR_MAX" "RAND_MAX"
2401
2403 Constants
2404 "BUFSIZ" "EOF" "FILENAME_MAX" "L_ctermid" "L_cuserid" "TMP_MAX"
2405
2407 Constants
2408 "CLK_TCK" "CLOCKS_PER_SEC"
2409
2411 Constants
2412 "R_OK" "SEEK_CUR" "SEEK_END" "SEEK_SET" "STDIN_FILENO"
2413 "STDOUT_FILENO" "STDERR_FILENO" "W_OK" "X_OK"
2414
2416 Constants
2417 "WNOHANG" "WUNTRACED"
2418 "WNOHANG" Do not suspend the calling process until a
2420 child process changes state but instead return
2421 immediately.
2422 "WUNTRACED" Catch stopped child processes.
2424 Macros "WIFEXITED" "WEXITSTATUS" "WIFSIGNALED" "WTERMSIG" "WIFSTOPPED"
2426 "WSTOPSIG"
2427 "WIFEXITED" WIFEXITED(${^CHILD_ERROR_NATIVE}) returns true
2429 if the child process exited normally (exit() or
2430 by falling off the end of main())
2431 "WEXITSTATUS" WEXITSTATUS(${^CHILD_ERROR_NATIVE}) returns the
2433 normal exit status of the child process (only
2434 meaningful if WIFEXITED(${^CHILD_ERROR_NATIVE})
2435 is true)
2436 "WIFSIGNALED" WIFSIGNALED(${^CHILD_ERROR_NATIVE}) returns
2438 true if the child process terminated because of
2439 a signal
2440 "WTERMSIG" WTERMSIG(${^CHILD_ERROR_NATIVE}) returns the
2442 signal the child process terminated for (only
2443 meaningful if
2444 WIFSIGNALED(${^CHILD_ERROR_NATIVE}) is true)
2445 "WIFSTOPPED" WIFSTOPPED(${^CHILD_ERROR_NATIVE}) returns true
2447 if the child process is currently stopped (can
2448 happen only if you specified the WUNTRACED flag
2449 to waitpid())
2450 "WSTOPSIG" WSTOPSIG(${^CHILD_ERROR_NATIVE}) returns the
2452 signal the child process was stopped for (only
2453 meaningful if
2454 WIFSTOPPED(${^CHILD_ERROR_NATIVE}) is true)
2455
2457 (Windows only.)
2458 Constants
2460 Added in Perl v5.24:
2461 "WSAEINTR" "WSAEBADF" "WSAEACCES" "WSAEFAULT" "WSAEINVAL"
2463 "WSAEMFILE" "WSAEWOULDBLOCK" "WSAEINPROGRESS" "WSAEALREADY"
2464 "WSAENOTSOCK" "WSAEDESTADDRREQ" "WSAEMSGSIZE" "WSAEPROTOTYPE"
2465 "WSAENOPROTOOPT" "WSAEPROTONOSUPPORT" "WSAESOCKTNOSUPPORT"
2466 "WSAEOPNOTSUPP" "WSAEPFNOSUPPORT" "WSAEAFNOSUPPORT"
2467 "WSAEADDRINUSE" "WSAEADDRNOTAVAIL" "WSAENETDOWN"
2468 "WSAENETUNREACH" "WSAENETRESET" "WSAECONNABORTED"
2469 "WSAECONNRESET" "WSAENOBUFS" "WSAEISCONN" "WSAENOTCONN"
2470 "WSAESHUTDOWN" "WSAETOOMANYREFS" "WSAETIMEDOUT"
2471 "WSAECONNREFUSED" "WSAELOOP" "WSAENAMETOOLONG" "WSAEHOSTDOWN"
2472 "WSAEHOSTUNREACH" "WSAENOTEMPTY" "WSAEPROCLIM" "WSAEUSERS"
2473 "WSAEDQUOT" "WSAESTALE" "WSAEREMOTE" "WSAEDISCON" "WSAENOMORE"
2474 "WSAECANCELLED" "WSAEINVALIDPROCTABLE" "WSAEINVALIDPROVIDER"
2475 "WSAEPROVIDERFAILEDINIT" "WSAEREFUSED"
2476perl v5.38.2 2023-11-30 POSIX(3pm)