3 POSIX - Perl interface to IEEE Std 1003.1
9 use POSIX qw(:errno_h :fcntl_h);
11 printf "EINTR is %d\n", EINTR;
13 $sess_id = POSIX::setsid();
15 $fd = POSIX::open($path, O_CREAT|O_EXCL|O_WRONLY, 0644);
16 # note: that's a filedescriptor, *NOT* a filehandle
20 The POSIX module permits you to access all (or nearly all) the standard
21 POSIX 1003.1 identifiers. Many of these identifiers have been given Perl-ish
22 interfaces. Things which are C<#defines> in C, like EINTR or O_NDELAY, are
23 automatically exported into your namespace. All functions are only exported
24 if you ask for them explicitly. Most likely people will prefer to use the
25 fully-qualified function names.
27 This document gives a condensed list of the features available in the POSIX
28 module. Consult your operating system's manpages for general information on
29 most features. Consult L<perlfunc> for functions which are noted as being
30 identical to Perl's builtin functions.
32 The first section describes POSIX functions from the 1003.1 specification.
33 The second section describes some classes for signal objects, TTY objects,
34 and other miscellaneous objects. The remaining sections list various
35 constants and macros in an organization which roughly follows IEEE Std
40 The POSIX module is probably the most complex Perl module supplied with
41 the standard distribution. It incorporates autoloading, namespace games,
42 and dynamic loading of code that's in Perl, C, or both. It's a great
47 A few functions are not implemented because they are C specific. If you
48 attempt to call these, they will print a message telling you that they
49 aren't implemented, and suggest using the Perl equivalent should one
50 exist. For example, trying to access the setjmp() call will elicit the
51 message "setjmp() is C-specific: use eval {} instead".
53 Furthermore, some evil vendors will claim 1003.1 compliance, but in fact
54 are not so: they will not pass the PCTS (POSIX Compliance Test Suites).
55 For example, one vendor may not define EDEADLK, or the semantics of the
56 errno values set by open(2) might not be quite right. Perl does not
57 attempt to verify POSIX compliance. That means you can currently
58 successfully say "use POSIX", and then later in your program you find
59 that your vendor has been lax and there's no usable ICANON macro after
60 all. This could be construed to be a bug.
68 This is identical to the C function C<_exit()>. It exits the program
69 immediately which means among other things buffered I/O is B<not> flushed.
73 This is identical to the C function C<abort()>. It terminates the
74 process with a C<SIGABRT> signal unless caught by a signal handler or
75 if the handler does not return normally (it e.g. does a C<longjmp>).
79 This is identical to Perl's builtin C<abs()> function, returning
80 the absolute value of its numerical argument.
84 Determines the accessibility of a file.
86 if( POSIX::access( "/", &POSIX::R_OK ) ){
87 print "have read permission\n";
90 Returns C<undef> on failure. Note: do not use C<access()> for
91 security purposes. Between the C<access()> call and the operation
92 you are preparing for the permissions might change: a classic
97 This is identical to the C function C<acos()>, returning
98 the arcus cosine of its numerical argument. See also L<Math::Trig>.
102 This is identical to Perl's builtin C<alarm()> function,
103 either for arming or disarming the C<SIGARLM> timer.
107 This is identical to the C function C<asctime()>. It returns
110 "Fri Jun 2 18:22:13 2000\n\0"
112 and it is called thusly
114 $asctime = asctime($sec, $min, $hour, $mday, $mon, $year,
115 $wday, $yday, $isdst);
117 The C<$mon> is zero-based: January equals C<0>. The C<$year> is
118 1900-based: 2001 equals C<101>. The C<$wday>, C<$yday>, and C<$isdst>
119 default to zero (and the first two are usually ignored anyway).
123 This is identical to the C function C<asin()>, returning
124 the arcus sine of its numerical argument. See also L<Math::Trig>.
128 Unimplemented, but you can use L<perlfunc/die> and the L<Carp> module
129 to achieve similar things.
133 This is identical to the C function C<atan()>, returning the
134 arcus tangent of its numerical argument. See also L<Math::Trig>.
138 This is identical to Perl's builtin C<atan2()> function, returning
139 the arcus tangent defined by its two numerical arguments, the I<y>
140 coordinate and the I<x> coordinate. See also L<Math::Trig>.
144 atexit() is C-specific: use C<END {}> instead, see L<perlsub>.
148 atof() is C-specific. Perl converts strings to numbers transparently.
149 If you need to force a scalar to a number, add a zero to it.
153 atoi() is C-specific. Perl converts strings to numbers transparently.
154 If you need to force a scalar to a number, add a zero to it.
155 If you need to have just the integer part, see L<perlfunc/int>.
159 atol() is C-specific. Perl converts strings to numbers transparently.
160 If you need to force a scalar to a number, add a zero to it.
161 If you need to have just the integer part, see L<perlfunc/int>.
165 bsearch() not supplied. For doing binary search on wordlists,
170 calloc() is C-specific. Perl does memory management transparently.
174 This is identical to the C function C<ceil()>, returning the smallest
175 integer value greater than or equal to the given numerical argument.
179 This is identical to Perl's builtin C<chdir()> function, allowing
180 one to change the working (default) directory, see L<perlfunc/chdir>.
184 This is identical to Perl's builtin C<chmod()> function, allowing
185 one to change file and directory permissions, see L<perlfunc/chmod>.
189 This is identical to Perl's builtin C<chown()> function, allowing one
190 to change file and directory owners and groups, see L<perlfunc/chown>.
194 Use the method C<IO::Handle::clearerr()> instead, to reset the error
195 state (if any) and EOF state (if any) of the given stream.
199 This is identical to the C function C<clock()>, returning the
200 amount of spent processor time in microseconds.
204 Close the file. This uses file descriptors such as those obtained by calling
207 $fd = POSIX::open( "foo", &POSIX::O_RDONLY );
210 Returns C<undef> on failure.
212 See also L<perlfunc/close>.
216 This is identical to Perl's builtin C<closedir()> function for closing
217 a directory handle, see L<perlfunc/closedir>.
221 This is identical to Perl's builtin C<cos()> function, for returning
222 the cosine of its numerical argument, see L<perlfunc/cos>.
223 See also L<Math::Trig>.
227 This is identical to the C function C<cosh()>, for returning
228 the hyperbolic cosine of its numeric argument. See also L<Math::Trig>.
232 Create a new file. This returns a file descriptor like the ones returned by
233 C<POSIX::open>. Use C<POSIX::close> to close the file.
235 $fd = POSIX::creat( "foo", 0611 );
238 See also L<perlfunc/sysopen> and its C<O_CREAT> flag.
242 Generates the path name for the controlling terminal.
244 $path = POSIX::ctermid();
248 This is identical to the C function C<ctime()> and equivalent
249 to C<asctime(localtime(...))>, see L</asctime> and L</localtime>.
253 Get the login name of the owner of the current process.
255 $name = POSIX::cuserid();
259 This is identical to the C function C<difftime()>, for returning
260 the time difference (in seconds) between two times (as returned
261 by C<time()>), see L</time>.
265 div() is C-specific, use L<perlfunc/int> on the usual C</> division and
270 This is similar to the C function C<dup()>, for duplicating a file
273 This uses file descriptors such as those obtained by calling
276 Returns C<undef> on failure.
280 This is similar to the C function C<dup2()>, for duplicating a file
281 descriptor to an another known file descriptor.
283 This uses file descriptors such as those obtained by calling
286 Returns C<undef> on failure.
290 Returns the value of errno.
292 $errno = POSIX::errno();
294 This identical to the numerical values of the C<$!>, see L<perlvar/$ERRNO>.
298 execl() is C-specific, see L<perlfunc/exec>.
302 execle() is C-specific, see L<perlfunc/exec>.
306 execlp() is C-specific, see L<perlfunc/exec>.
310 execv() is C-specific, see L<perlfunc/exec>.
314 execve() is C-specific, see L<perlfunc/exec>.
318 execvp() is C-specific, see L<perlfunc/exec>.
322 This is identical to Perl's builtin C<exit()> function for exiting the
323 program, see L<perlfunc/exit>.
327 This is identical to Perl's builtin C<exp()> function for
328 returning the exponent (I<e>-based) of the numerical argument,
333 This is identical to Perl's builtin C<abs()> function for returning
334 the absolute value of the numerical argument, see L<perlfunc/abs>.
338 Use method C<IO::Handle::close()> instead, or see L<perlfunc/close>.
342 This is identical to Perl's builtin C<fcntl()> function,
343 see L<perlfunc/fcntl>.
347 Use method C<IO::Handle::new_from_fd()> instead, or see L<perlfunc/open>.
351 Use method C<IO::Handle::eof()> instead, or see L<perlfunc/eof>.
355 Use method C<IO::Handle::error()> instead.
359 Use method C<IO::Handle::flush()> instead.
360 See also L<perlvar/$OUTPUT_AUTOFLUSH>.
364 Use method C<IO::Handle::getc()> instead, or see L<perlfunc/read>.
368 Use method C<IO::Seekable::getpos()> instead, or see L<L/seek>.
372 Use method C<IO::Handle::gets()> instead. Similar to E<lt>E<gt>, also known
373 as L<perlfunc/readline>.
377 Use method C<IO::Handle::fileno()> instead, or see L<perlfunc/fileno>.
381 This is identical to the C function C<floor()>, returning the largest
382 integer value less than or equal to the numerical argument.
386 This is identical to the C function C<fmod()>.
390 It returns the remainder C<$r = $x - $n*$y>, where C<$n = trunc($x/$y)>.
391 The C<$r> has the same sign as C<$x> and magnitude (absolute value)
392 less than the magnitude of C<$y>.
396 Use method C<IO::File::open()> instead, or see L<perlfunc/open>.
400 This is identical to Perl's builtin C<fork()> function
401 for duplicating the current process, see L<perlfunc/fork>
402 and L<perlfork> if you are in Windows.
406 Retrieves the value of a configurable limit on a file or directory. This
407 uses file descriptors such as those obtained by calling C<POSIX::open>.
409 The following will determine the maximum length of the longest allowable
410 pathname on the filesystem which holds C</tmp/foo>.
412 $fd = POSIX::open( "/tmp/foo", &POSIX::O_RDONLY );
413 $path_max = POSIX::fpathconf( $fd, &POSIX::_PC_PATH_MAX );
415 Returns C<undef> on failure.
419 fprintf() is C-specific, see L<perlfunc/printf> instead.
423 fputc() is C-specific, see L<perlfunc/print> instead.
427 fputs() is C-specific, see L<perlfunc/print> instead.
431 fread() is C-specific, see L<perlfunc/read> instead.
435 free() is C-specific. Perl does memory management transparently.
439 freopen() is C-specific, see L<perlfunc/open> instead.
443 Return the mantissa and exponent of a floating-point number.
445 ($mantissa, $exponent) = POSIX::frexp( 1.234e56 );
449 fscanf() is C-specific, use E<lt>E<gt> and regular expressions instead.
453 Use method C<IO::Seekable::seek()> instead, or see L<perlfunc/seek>.
457 Use method C<IO::Seekable::setpos()> instead, or seek L<perlfunc/seek>.
461 Get file status. This uses file descriptors such as those obtained by
462 calling C<POSIX::open>. The data returned is identical to the data from
463 Perl's builtin C<stat> function.
465 $fd = POSIX::open( "foo", &POSIX::O_RDONLY );
466 @stats = POSIX::fstat( $fd );
470 Use method C<IO::Seekable::tell()> instead, or see L<perlfunc/tell>.
474 fwrite() is C-specific, see L<perlfunc/print> instead.
478 This is identical to Perl's builtin C<getc()> function,
479 see L<perlfunc/getc>.
483 Returns one character from STDIN. Identical to Perl's C<getc()>,
484 see L<perlfunc/getc>.
488 Returns the name of the current working directory.
493 Returns the effective group identifier. Similar to Perl' s builtin
494 variable C<$(>, see L<perlvar/$EGID>.
498 Returns the value of the specified enironment variable.
499 The same information is available through the C<%ENV> array.
503 Returns the effective user identifier. Identical to Perl's builtin C<$E<gt>>
504 variable, see L<perlvar/$EUID>.
508 Returns the user's real group identifier. Similar to Perl's builtin
509 variable C<$)>, see L<perlvar/$GID>.
513 This is identical to Perl's builtin C<getgrgid()> function for
514 returning group entries by group identifiers, see
515 L<perlfunc/getgrgid>.
519 This is identical to Perl's builtin C<getgrnam()> function for
520 returning group entries by group names, see L<perlfunc/getgrnam>.
524 Returns the ids of the user's supplementary groups. Similar to Perl's
525 builtin variable C<$)>, see L<perlvar/$GID>.
529 This is identical to Perl's builtin C<getlogin()> function for
530 returning the user name associated with the current session, see
531 L<perlfunc/getlogin>.
535 This is identical to Perl's builtin C<getpgrp()> function for
536 returning the prcess group identifier of the current process, see
541 Returns the process identifier. Identical to Perl's builtin
542 variable C<$$>, see L<perlvar/$PID>.
546 This is identical to Perl's builtin C<getppid()> function for
547 returning the process identifier of the parent process of the current
548 process , see L<perlfunc/getppid>.
552 This is identical to Perl's builtin C<getpwnam()> function for
553 returning user entries by user names, see L<perlfunc/getpwnam>.
557 This is identical to Perl's builtin C<getpwuid()> function for
558 returning user entries by user identifiers, see L<perlfunc/getpwuid>.
562 Returns one line from C<STDIN>, similar to E<lt>E<gt>, also known
563 as the C<readline()> function, see L<perlfunc/readline>.
565 B<NOTE>: if you have C programs that still use C<gets()>, be very
566 afraid. The C<gets()> function is a source of endless grief because
567 it has no buffer overrun checks. It should B<never> be used. The
568 C<fgets()> function should be preferred instead.
572 Returns the user's identifier. Identical to Perl's builtin C<$E<lt>> variable,
577 This is identical to Perl's builtin C<gmtime()> function for
578 converting seconds since the epoch to a date in Greenwich Mean Time,
579 see L<perlfunc/gmtime>.
583 This is identical to the C function, except that it can apply to a single
584 character or to a whole string. Consider using regular expressions and the
585 C</[[:alnum:]]/> construct instead, or possibly the C</\w/> construct.
589 This is identical to the C function, except that it can apply to a single
590 character or to a whole string. Consider using regular expressions and the
591 C</[[:alpha:]]/> construct instead.
595 Returns a boolean indicating whether the specified filehandle is connected
596 to a tty. Similar to the C<-t> operator, see L<perlfunc/-X>.
600 This is identical to the C function, except that it can apply to a single
601 character or to a whole string. Consider using regular expressions and the
602 C</[[:cntrl:]]/> construct instead.
606 This is identical to the C function, except that it can apply to a single
607 character or to a whole string. Consider using regular expressions and the
608 C</[[:digit:]]/> construct instead, or the C</\d/> construct.
612 This is identical to the C function, except that it can apply to a single
613 character or to a whole string. Consider using regular expressions and the
614 C</[[:graph:]]/> construct instead.
618 This is identical to the C function, except that it can apply to a single
619 character or to a whole string. Consider using regular expressions and the
620 C</[[:lower:]]/> construct instead. Do B<not> use C</[a-z]/>.
624 This is identical to the C function, except that it can apply to a single
625 character or to a whole string. Consider using regular expressions and the
626 C</[[:print:]]/> construct instead.
630 This is identical to the C function, except that it can apply to a single
631 character or to a whole string. Consider using regular expressions and the
632 C</[[:punct:]]/> construct instead.
636 This is identical to the C function, except that it can apply to a single
637 character or to a whole string. Consider using regular expressions and the
638 C</[[:space:]]/> construct instead, or the C</\s/> construct.
639 (Note that C</\s/> and C</[[:space:]]/> are slightly different in that
640 C</[[:space:]]/> can normally match a vertical tab, while C</\s/> does
645 This is identical to the C function, except that it can apply to a single
646 character or to a whole string. Consider using regular expressions and the
647 C</[[:upper:]]/> construct instead. Do B<not> use C</[A-Z]/>.
651 This is identical to the C function, except that it can apply to a single
652 character or to a whole string. Consider using regular expressions and the
653 C</[[:xdigit:]]/> construct instead, or simply C</[0-9a-f]/i>.
657 This is identical to Perl's builtin C<kill()> function for sending
658 signals to processes (often to terminate them), see L<perlfunc/kill>.
662 (For returning absolute values of long integers.)
663 labs() is C-specific, see L<perlfunc/abs> instead.
667 This is identical to the C function C<ldexp()>
668 for multiplying floating point numbers with powers of two.
670 $x_quadrupled = POSIX::ldexp($x, 2);
674 (For computing dividends of long integers.)
675 ldiv() is C-specific, use C</> and C<int()> instead.
679 This is identical to Perl's builtin C<link()> function
680 for creating hard links into files, see L<perlfunc/link>.
684 Get numeric formatting information. Returns a reference to a hash
685 containing the current locale formatting values.
687 Here is how to query the database for the B<de> (Deutsch or German) locale.
689 $loc = POSIX::setlocale( &POSIX::LC_ALL, "de" );
690 print "Locale = $loc\n";
691 $lconv = POSIX::localeconv();
692 print "decimal_point = ", $lconv->{decimal_point}, "\n";
693 print "thousands_sep = ", $lconv->{thousands_sep}, "\n";
694 print "grouping = ", $lconv->{grouping}, "\n";
695 print "int_curr_symbol = ", $lconv->{int_curr_symbol}, "\n";
696 print "currency_symbol = ", $lconv->{currency_symbol}, "\n";
697 print "mon_decimal_point = ", $lconv->{mon_decimal_point}, "\n";
698 print "mon_thousands_sep = ", $lconv->{mon_thousands_sep}, "\n";
699 print "mon_grouping = ", $lconv->{mon_grouping}, "\n";
700 print "positive_sign = ", $lconv->{positive_sign}, "\n";
701 print "negative_sign = ", $lconv->{negative_sign}, "\n";
702 print "int_frac_digits = ", $lconv->{int_frac_digits}, "\n";
703 print "frac_digits = ", $lconv->{frac_digits}, "\n";
704 print "p_cs_precedes = ", $lconv->{p_cs_precedes}, "\n";
705 print "p_sep_by_space = ", $lconv->{p_sep_by_space}, "\n";
706 print "n_cs_precedes = ", $lconv->{n_cs_precedes}, "\n";
707 print "n_sep_by_space = ", $lconv->{n_sep_by_space}, "\n";
708 print "p_sign_posn = ", $lconv->{p_sign_posn}, "\n";
709 print "n_sign_posn = ", $lconv->{n_sign_posn}, "\n";
713 This is identical to Perl's builtin C<localtime()> function for
714 converting seconds since the epoch to a date see L<perlfunc/localtime>.
718 This is identical to Perl's builtin C<log()> function,
719 returning the natural (I<e>-based) logarithm of the numerical argument,
724 This is identical to the C function C<log10()>,
725 returning the 10-base logarithm of the numerical argument.
728 sub log10 { log($_[0]) / log(10) }
732 sub log10 { log($_[0]) / 2.30258509299405 }
736 sub log10 { log($_[0]) * 0.434294481903252 }
740 longjmp() is C-specific: use L<perlfunc/die> instead.
744 Move the file's read/write position. This uses file descriptors such as
745 those obtained by calling C<POSIX::open>.
747 $fd = POSIX::open( "foo", &POSIX::O_RDONLY );
748 $off_t = POSIX::lseek( $fd, 0, &POSIX::SEEK_SET );
750 Returns C<undef> on failure.
754 malloc() is C-specific. Perl does memory management transparently.
758 This is identical to the C function C<mblen()>.
759 Perl does not have any support for the wide and multibyte
760 characters of the C standards, so this might be a rather
765 This is identical to the C function C<mbstowcs()>.
766 Perl does not have any support for the wide and multibyte
767 characters of the C standards, so this might be a rather
772 This is identical to the C function C<mbtowc()>.
773 Perl does not have any support for the wide and multibyte
774 characters of the C standards, so this might be a rather
779 memchr() is C-specific, see L<perlfunc/index> instead.
783 memcmp() is C-specific, use C<eq> instead, see L<perlop>.
787 memcpy() is C-specific, use C<=>, see L<perlop>, or see L<perlfunc/substr>.
791 memmove() is C-specific, use C<=>, see L<perlop>, or see L<perlfunc/substr>.
795 memset() is C-specific, use C<x> instead, see L<perlop>.
799 This is identical to Perl's builtin C<mkdir()> function
800 for creating directories, see L<perlfunc/mkdir>.
804 This is similar to the C function C<mkfifo()> for creating
807 if (mkfifo($path, $mode)) { ....
809 Returns C<undef> on failure. The C<$mode> is similar to the
810 mode of C<mkdir()>, see L<perlfunc/mkdir>.
814 Convert date/time info to a calendar time.
818 mktime(sec, min, hour, mday, mon, year, wday = 0, yday = 0, isdst = 0)
820 The month (C<mon>), weekday (C<wday>), and yearday (C<yday>) begin at zero.
821 I.e. January is 0, not 1; Sunday is 0, not 1; January 1st is 0, not 1. The
822 year (C<year>) is given in years since 1900. I.e. The year 1995 is 95; the
823 year 2001 is 101. Consult your system's C<mktime()> manpage for details
824 about these and the other arguments.
826 Calendar time for December 12, 1995, at 10:30 am.
828 $time_t = POSIX::mktime( 0, 30, 10, 12, 11, 95 );
829 print "Date = ", POSIX::ctime($time_t);
831 Returns C<undef> on failure.
835 Return the integral and fractional parts of a floating-point number.
837 ($fractional, $integral) = POSIX::modf( 3.14 );
841 This is similar to the C function C<nice()>, for changing
842 the scheduling preference of the current process. Positive
843 arguments mean more polite process, negative values more
844 needy process. Normal user processes can only be more polite.
846 Returns C<undef> on failure.
850 offsetof() is C-specific, you probably want to see L<perlfunc/pack> instead.
854 Open a file for reading for writing. This returns file descriptors, not
855 Perl filehandles. Use C<POSIX::close> to close the file.
857 Open a file read-only with mode 0666.
859 $fd = POSIX::open( "foo" );
861 Open a file for read and write.
863 $fd = POSIX::open( "foo", &POSIX::O_RDWR );
865 Open a file for write, with truncation.
867 $fd = POSIX::open( "foo", &POSIX::O_WRONLY | &POSIX::O_TRUNC );
869 Create a new file with mode 0640. Set up the file for writing.
871 $fd = POSIX::open( "foo", &POSIX::O_CREAT | &POSIX::O_WRONLY, 0640 );
873 Returns C<undef> on failure.
875 See also L<perlfunc/sysopen>.
879 Open a directory for reading.
881 $dir = POSIX::opendir( "/tmp" );
882 @files = POSIX::readdir( $dir );
883 POSIX::closedir( $dir );
885 Returns C<undef> on failure.
889 Retrieves the value of a configurable limit on a file or directory.
891 The following will determine the maximum length of the longest allowable
892 pathname on the filesystem which holds C</tmp>.
894 $path_max = POSIX::pathconf( "/tmp", &POSIX::_PC_PATH_MAX );
896 Returns C<undef> on failure.
900 This is similar to the C function C<pause()>, which suspends
901 the execution of the current process until a signal is received.
903 Returns C<undef> on failure.
907 This is identical to the C function C<perror()>, which outputs to the
908 standard error stream the specified message followed by ": " and the
909 current error string. Use the C<warn()> function and the C<$!>
910 variable instead, see L<perlfunc/warn> and L<perlvar/$ERRNO>.
914 Create an interprocess channel. This returns file descriptors like those
915 returned by C<POSIX::open>.
917 ($fd0, $fd1) = POSIX::pipe();
918 POSIX::write( $fd0, "hello", 5 );
919 POSIX::read( $fd1, $buf, 5 );
921 See also L<perlfunc/pipe>.
925 Computes C<$x> raised to the power C<$exponent>.
927 $ret = POSIX::pow( $x, $exponent );
929 You can also use the C<**> operator, see L<perlop>.
933 Formats and prints the specified arguments to STDOUT.
934 See also L<perlfunc/printf>.
938 putc() is C-specific, see L<perlfunc/print> instead.
942 putchar() is C-specific, see L<perlfunc/print> instead.
946 puts() is C-specific, see L<perlfunc/print> instead.
950 qsort() is C-specific, see L<perlfunc/sort> instead.
954 Sends the specified signal to the current process.
955 See also L<perlfunc/kill> and the C<$$> in L<perlvar/$PID>.
959 C<rand()> is non-portable, see L<perlfunc/rand> instead.
963 Read from a file. This uses file descriptors such as those obtained by
964 calling C<POSIX::open>. If the buffer C<$buf> is not large enough for the
965 read then Perl will extend it to make room for the request.
967 $fd = POSIX::open( "foo", &POSIX::O_RDONLY );
968 $bytes = POSIX::read( $fd, $buf, 3 );
970 Returns C<undef> on failure.
972 See also L<perlfunc/sysread>.
976 This is identical to Perl's builtin C<readdir()> function
977 for reading directory entries, see L<perlfunc/readdir>.
981 realloc() is C-specific. Perl does memory management transparently.
985 This is identical to Perl's builtin C<unlink()> function
986 for removing files, see L<perlfunc/unlink>.
990 This is identical to Perl's builtin C<rename()> function
991 for renaming files, see L<perlfunc/rename>.
995 Seeks to the beginning of the file.
999 This is identical to Perl's builtin C<rewinddir()> function for
1000 rewinding directory entry streams, see L<perlfunc/rewinddir>.
1004 This is identical to Perl's builtin C<rmdir()> function
1005 for removing (empty) directories, see L<perlfunc/rmdir>.
1009 scanf() is C-specific, use E<lt>E<gt> and regular expressions instead,
1014 Sets the real group identifier and the effective group identifier for
1015 this process. Similar to assigning a value to the Perl's builtin
1016 C<$)> variable, see L<perlvar/$GID>, except that the latter
1017 will change only the real user identifier, and that the setgid()
1018 uses only a single numeric argument, as opposed to a space-separated
1023 C<setjmp()> is C-specific: use C<eval {}> instead,
1024 see L<perlfunc/eval>.
1028 Modifies and queries program's locale. The following examples assume
1030 use POSIX qw(setlocale LC_ALL LC_CTYPE);
1034 The following will set the traditional UNIX system locale behavior
1035 (the second argument C<"C">).
1037 $loc = setlocale( LC_ALL, "C" );
1039 The following will query the current LC_CTYPE category. (No second
1040 argument means 'query'.)
1042 $loc = setlocale( LC_CTYPE );
1044 The following will set the LC_CTYPE behaviour according to the locale
1045 environment variables (the second argument C<"">).
1046 Please see your systems C<setlocale(3)> documentation for the locale
1047 environment variables' meaning or consult L<perllocale>.
1049 $loc = setlocale( LC_CTYPE, "" );
1051 The following will set the LC_COLLATE behaviour to Argentinian
1052 Spanish. B<NOTE>: The naming and availability of locales depends on
1053 your operating system. Please consult L<perllocale> for how to find
1054 out which locales are available in your system.
1056 $loc = setlocale( LC_ALL, "es_AR.ISO8859-1" );
1060 This is similar to the C function C<setpgid()> for
1061 setting the process group identifier of the current process.
1063 Returns C<undef> on failure.
1067 This is identical to the C function C<setsid()> for
1068 setting the session identifier of the current process.
1072 Sets the real user identifier and the effective user identifier for
1073 this process. Similar to assigning a value to the Perl's builtin
1074 C<$E<lt>> variable, see L<perlvar/$UID>, except that the latter
1075 will change only the real user identifier.
1079 Detailed signal management. This uses C<POSIX::SigAction> objects for the
1080 C<action> and C<oldaction> arguments. Consult your system's C<sigaction>
1081 manpage for details.
1085 sigaction(sig, action, oldaction = 0)
1087 Returns C<undef> on failure.
1091 siglongjmp() is C-specific: use L<perlfunc/die> instead.
1095 Examine signals that are blocked and pending. This uses C<POSIX::SigSet>
1096 objects for the C<sigset> argument. Consult your system's C<sigpending>
1097 manpage for details.
1103 Returns C<undef> on failure.
1107 Change and/or examine calling process's signal mask. This uses
1108 C<POSIX::SigSet> objects for the C<sigset> and C<oldsigset> arguments.
1109 Consult your system's C<sigprocmask> manpage for details.
1113 sigprocmask(how, sigset, oldsigset = 0)
1115 Returns C<undef> on failure.
1119 C<sigsetjmp()> is C-specific: use C<eval {}> instead,
1120 see L<perlfunc/eval>.
1124 Install a signal mask and suspend process until signal arrives. This uses
1125 C<POSIX::SigSet> objects for the C<signal_mask> argument. Consult your
1126 system's C<sigsuspend> manpage for details.
1130 sigsuspend(signal_mask)
1132 Returns C<undef> on failure.
1136 This is identical to Perl's builtin C<sin()> function
1137 for returning the sine of the numerical argument,
1138 see L<perlfunc/sin>. See also L<Math::Trig>.
1142 This is identical to the C function C<sinh()>
1143 for returning the hyperbolic sine of the numerical argument.
1144 See also L<Math::Trig>.
1148 This is functionally identical to Perl's builtin C<sleep()> function
1149 for suspending the execution of the current for process for certain
1150 number of seconds, see L<perlfunc/sleep>. There is one signifanct
1151 difference, however: C<POSIX::sleep()> returns the number of
1152 B<unslept> seconds, while the C<CORE::sleep()> returns the
1153 number of slept seconds.
1157 This is similar to Perl's builtin C<sprintf()> function
1158 for returning a string that has the arguments formatted as requested,
1159 see L<perlfunc/sprintf>.
1163 This is identical to Perl's builtin C<sqrt()> function.
1164 for returning the square root of the numerical argument,
1165 see L<perlfunc/sqrt>.
1169 Give a seed the pseudorandom number generator, see L<perlfunc/srand>.
1173 sscanf() is C-specific, use regular expressions instead,
1178 This is identical to Perl's builtin C<stat()> function
1179 for retutning information about files and directories.
1183 strcat() is C-specific, use C<.=> instead, see L<perlop>.
1187 strchr() is C-specific, see L<perlfunc/index> instead.
1191 strcmp() is C-specific, use C<eq> or C<cmp> instead, see L<perlop>.
1195 This is identical to the C function C<strcoll()>
1196 for collating (comparing) strings transformed using
1197 the C<strxfrm()> function. Not really needed since
1198 Perl can do this transparently, see L<perllocale>.
1202 strcpy() is C-specific, use C<=> instead, see L<perlop>.
1206 strcspn() is C-specific, use regular expressions instead,
1211 Returns the error string for the specified errno.
1212 Identical to the string form of the C<$!>, see L<perlvar/$ERRNO>.
1216 Convert date and time information to string. Returns the string.
1220 strftime(fmt, sec, min, hour, mday, mon, year, wday = -1, yday = -1, isdst = -1)
1222 The month (C<mon>), weekday (C<wday>), and yearday (C<yday>) begin at zero.
1223 I.e. January is 0, not 1; Sunday is 0, not 1; January 1st is 0, not 1. The
1224 year (C<year>) is given in years since 1900. I.e., the year 1995 is 95; the
1225 year 2001 is 101. Consult your system's C<strftime()> manpage for details
1226 about these and the other arguments.
1227 If you want your code to be portable, your format (C<fmt>) argument
1228 should use only the conversion specifiers defined by the ANSI C
1229 standard. These are C<aAbBcdHIjmMpSUwWxXyYZ%>.
1230 The given arguments are made consistent
1231 as though by calling C<mktime()> before calling your system's
1232 C<strftime()> function, except that the C<isdst> value is not affected.
1234 The string for Tuesday, December 12, 1995.
1236 $str = POSIX::strftime( "%A, %B %d, %Y", 0, 0, 0, 12, 11, 95, 2 );
1241 strlen() is C-specific, use C<length()> instead, see L<perlfunc/length>.
1245 strncat() is C-specific, use C<.=> instead, see L<perlop>.
1249 strncmp() is C-specific, use C<eq> instead, see L<perlop>.
1253 strncpy() is C-specific, use C<=> instead, see L<perlop>.
1257 strpbrk() is C-specific, use regular expressions instead,
1262 strrchr() is C-specific, see L<perlfunc/rindex> instead.
1266 strspn() is C-specific, use regular expressions instead,
1271 This is identical to Perl's builtin C<index()> function,
1272 see L<perlfunc/index>.
1276 String to double translation. Returns the parsed number and the number
1277 of characters in the unparsed portion of the string. Truly
1278 POSIX-compliant systems set $! ($ERRNO) to indicate a translation
1279 error, so clear $! before calling strtod. However, non-POSIX systems
1280 may not check for overflow, and therefore will never set $!.
1282 strtod should respect any POSIX I<setlocale()> settings.
1284 To parse a string $str as a floating point number use
1287 ($num, $n_unparsed) = POSIX::strtod($str);
1289 The second returned item and $! can be used to check for valid input:
1291 if (($str eq '') || ($n_unparsed != 0) || !$!) {
1292 die "Non-numeric input $str" . $! ? ": $!\n" : "\n";
1295 When called in a scalar context strtod returns the parsed number.
1299 strtok() is C-specific, use regular expressions instead, see
1300 L<perlre>, or L<perlfunc/split>.
1304 String to (long) integer translation. Returns the parsed number and
1305 the number of characters in the unparsed portion of the string. Truly
1306 POSIX-compliant systems set $! ($ERRNO) to indicate a translation
1307 error, so clear $! before calling strtol. However, non-POSIX systems
1308 may not check for overflow, and therefore will never set $!.
1310 strtol should respect any POSIX I<setlocale()> settings.
1312 To parse a string $str as a number in some base $base use
1315 ($num, $n_unparsed) = POSIX::strtol($str, $base);
1317 The base should be zero or between 2 and 36, inclusive. When the base
1318 is zero or omitted strtol will use the string itself to determine the
1319 base: a leading "0x" or "0X" means hexadecimal; a leading "0" means
1320 octal; any other leading characters mean decimal. Thus, "1234" is
1321 parsed as a decimal number, "01234" as an octal number, and "0x1234"
1322 as a hexadecimal number.
1324 The second returned item and $! can be used to check for valid input:
1326 if (($str eq '') || ($n_unparsed != 0) || !$!) {
1327 die "Non-numeric input $str" . $! ? ": $!\n" : "\n";
1330 When called in a scalar context strtol returns the parsed number.
1334 String to unsigned (long) integer translation. strtoul() is identical
1335 to strtol() except that strtoul() only parses unsigned integers. See
1336 L</strtol> for details.
1338 Note: Some vendors supply strtod() and strtol() but not strtoul().
1339 Other vendors that do supply strtoul() parse "-1" as a valid value.
1343 String transformation. Returns the transformed string.
1345 $dst = POSIX::strxfrm( $src );
1347 Used in conjunction with the C<strcoll()> function, see L</strcoll>.
1349 Not really needed since Perl can do this transparently, see
1354 Retrieves values of system configurable variables.
1356 The following will get the machine's clock speed.
1358 $clock_ticks = POSIX::sysconf( &POSIX::_SC_CLK_TCK );
1360 Returns C<undef> on failure.
1364 This is identical to Perl's builtin C<system()> function, see
1369 This is identical to the C function C<tan()>, returning the
1370 tangent of the numerical argument. See also L<Math::Trig>.
1374 This is identical to the C function C<tanh()>, returning the
1375 hyperbolic tangent of the numerical argument. See also L<Math::Trig>.
1379 This is similar to the C function C<tcdrain()> for draining
1380 the output queue of its argument stream.
1382 Returns C<undef> on failure.
1386 This is similar to the C function C<tcflow()> for controlling
1387 the flow of its argument stream.
1389 Returns C<undef> on failure.
1393 This is similar to the C function C<tcflush()> for flushing
1394 the I/O buffers of its argumeny stream.
1396 Returns C<undef> on failure.
1400 This is identical to the C function C<tcgetpgrp()> for returning the
1401 process group identifier of the foreground process group of the controlling
1406 This is similar to the C function C<tcsendbreak()> for sending
1407 a break on its argument stream.
1409 Returns C<undef> on failure.
1413 This is similar to the C function C<tcsetpgrp()> for setting the
1414 process group identifier of the foreground process group of the controlling
1417 Returns C<undef> on failure.
1421 This is identical to Perl's builtin C<time()> function
1422 for returning the number of seconds since the epoch
1423 (whatever it is for the system), see L<perlfunc/time>.
1427 The times() function returns elapsed realtime since some point in the past
1428 (such as system startup), user and system times for this process, and user
1429 and system times used by child processes. All times are returned in clock
1432 ($realtime, $user, $system, $cuser, $csystem) = POSIX::times();
1434 Note: Perl's builtin C<times()> function returns four values, measured in
1439 Use method C<IO::File::new_tmpfile()> instead, or see L<File::Temp>.
1443 Returns a name for a temporary file.
1445 $tmpfile = POSIX::tmpnam();
1447 For security reasons, which are probably detailed in your system's
1448 documentation for the C library tmpnam() function, this interface
1449 should not be used; instead see L<File::Temp>.
1453 This is identical to the C function, except that it can apply to a single
1454 character or to a whole string. Consider using the C<lc()> function,
1455 see L<perlfunc/lc>, or the equivalent C<\L> operator inside doublequotish
1460 This is identical to the C function, except that it can apply to a single
1461 character or to a whole string. Consider using the C<uc()> function,
1462 see L<perlfunc/uc>, or the equivalent C<\U> operator inside doublequotish
1467 This is identical to the C function C<ttyname()> for returning the
1468 name of the current terminal.
1472 Retrieves the time conversion information from the C<tzname> variable.
1475 ($std, $dst) = POSIX::tzname();
1479 This is identical to the C function C<tzset()> for setting
1480 the current timezone based on the environment variable C<TZ>,
1481 to be used by C<ctime()>, C<localtime()>, C<mktime()>, and C<strftime()>
1486 This is identical to Perl's builtin C<umask()> function
1487 for setting (and querying) the file creation permission mask,
1488 see L<perlfunc/umask>.
1492 Get name of current operating system.
1494 ($sysname, $nodename, $release, $version, $machine) = POSIX::uname();
1496 Note that the actual meanings of the various fields are not
1497 that well standardized, do not expect any great portability.
1498 The C<$sysname> might be the name of the operating system,
1499 the C<$nodename> might be the name of the host, the C<$release>
1500 might be the (major) release number of the operating system,
1501 the C<$version> might be the (minor) release number of the
1502 operating system, and the C<$machine> might be a hardware identifier.
1507 Use method C<IO::Handle::ungetc()> instead.
1511 This is identical to Perl's builtin C<unlink()> function
1512 for removing files, see L<perlfunc/unlink>.
1516 This is identical to Perl's builtin C<utime()> function
1517 for changing the time stamps of files and directories,
1518 see L<perlfunc/utime>.
1522 vfprintf() is C-specific, see L<perlfunc/printf> instead.
1526 vprintf() is C-specific, see L<perlfunc/printf> instead.
1530 vsprintf() is C-specific, see L<perlfunc/sprintf> instead.
1534 This is identical to Perl's builtin C<wait()> function,
1535 see L<perlfunc/wait>.
1539 Wait for a child process to change state. This is identical to Perl's
1540 builtin C<waitpid()> function, see L<perlfunc/waitpid>.
1542 $pid = POSIX::waitpid( -1, POSIX::WNOHANG );
1543 print "status = ", ($? / 256), "\n";
1547 This is identical to the C function C<wcstombs()>.
1548 Perl does not have any support for the wide and multibyte
1549 characters of the C standards, so this might be a rather
1554 This is identical to the C function C<wctomb()>.
1555 Perl does not have any support for the wide and multibyte
1556 characters of the C standards, so this might be a rather
1561 Write to a file. This uses file descriptors such as those obtained by
1562 calling C<POSIX::open>.
1564 $fd = POSIX::open( "foo", &POSIX::O_WRONLY );
1566 $bytes = POSIX::write( $b, $buf, 5 );
1568 Returns C<undef> on failure.
1570 See also L<perlfunc/syswrite>.
1576 =head2 POSIX::SigAction
1582 Creates a new C<POSIX::SigAction> object which corresponds to the C
1583 C<struct sigaction>. This object will be destroyed automatically when it is
1584 no longer needed. The first parameter is the fully-qualified name of a sub
1585 which is a signal-handler. The second parameter is a C<POSIX::SigSet>
1586 object, it defaults to the empty set. The third parameter contains the
1587 C<sa_flags>, it defaults to 0.
1589 $sigset = POSIX::SigSet->new(SIGINT, SIGQUIT);
1590 $sigaction = POSIX::SigAction->new( 'main::handler', $sigset, &POSIX::SA_NOCLDSTOP );
1592 This C<POSIX::SigAction> object should be used with the C<POSIX::sigaction()>
1597 =head2 POSIX::SigSet
1603 Create a new SigSet object. This object will be destroyed automatically
1604 when it is no longer needed. Arguments may be supplied to initialize the
1607 Create an empty set.
1609 $sigset = POSIX::SigSet->new;
1611 Create a set with SIGUSR1.
1613 $sigset = POSIX::SigSet->new( &POSIX::SIGUSR1 );
1617 Add a signal to a SigSet object.
1619 $sigset->addset( &POSIX::SIGUSR2 );
1621 Returns C<undef> on failure.
1625 Remove a signal from the SigSet object.
1627 $sigset->delset( &POSIX::SIGUSR2 );
1629 Returns C<undef> on failure.
1633 Initialize the SigSet object to be empty.
1635 $sigset->emptyset();
1637 Returns C<undef> on failure.
1641 Initialize the SigSet object to include all signals.
1645 Returns C<undef> on failure.
1649 Tests the SigSet object to see if it contains a specific signal.
1651 if( $sigset->ismember( &POSIX::SIGUSR1 ) ){
1652 print "contains SIGUSR1\n";
1657 =head2 POSIX::Termios
1663 Create a new Termios object. This object will be destroyed automatically
1664 when it is no longer needed. A Termios object corresponds to the termios
1665 C struct. new() mallocs a new one, getattr() fills it from a file descriptor,
1666 and setattr() sets a file descriptor's parameters to match Termios' contents.
1668 $termios = POSIX::Termios->new;
1672 Get terminal control attributes.
1674 Obtain the attributes for stdin.
1678 Obtain the attributes for stdout.
1680 $termios->getattr( 1 )
1682 Returns C<undef> on failure.
1686 Retrieve a value from the c_cc field of a termios object. The c_cc field is
1687 an array so an index must be specified.
1689 $c_cc[1] = $termios->getcc(1);
1693 Retrieve the c_cflag field of a termios object.
1695 $c_cflag = $termios->getcflag;
1699 Retrieve the c_iflag field of a termios object.
1701 $c_iflag = $termios->getiflag;
1705 Retrieve the input baud rate.
1707 $ispeed = $termios->getispeed;
1711 Retrieve the c_lflag field of a termios object.
1713 $c_lflag = $termios->getlflag;
1717 Retrieve the c_oflag field of a termios object.
1719 $c_oflag = $termios->getoflag;
1723 Retrieve the output baud rate.
1725 $ospeed = $termios->getospeed;
1729 Set terminal control attributes.
1731 Set attributes immediately for stdout.
1733 $termios->setattr( 1, &POSIX::TCSANOW );
1735 Returns C<undef> on failure.
1739 Set a value in the c_cc field of a termios object. The c_cc field is an
1740 array so an index must be specified.
1742 $termios->setcc( &POSIX::VEOF, 1 );
1746 Set the c_cflag field of a termios object.
1748 $termios->setcflag( $c_cflag | &POSIX::CLOCAL );
1752 Set the c_iflag field of a termios object.
1754 $termios->setiflag( $c_iflag | &POSIX::BRKINT );
1758 Set the input baud rate.
1760 $termios->setispeed( &POSIX::B9600 );
1762 Returns C<undef> on failure.
1766 Set the c_lflag field of a termios object.
1768 $termios->setlflag( $c_lflag | &POSIX::ECHO );
1772 Set the c_oflag field of a termios object.
1774 $termios->setoflag( $c_oflag | &POSIX::OPOST );
1778 Set the output baud rate.
1780 $termios->setospeed( &POSIX::B9600 );
1782 Returns C<undef> on failure.
1784 =item Baud rate values
1786 B38400 B75 B200 B134 B300 B1800 B150 B0 B19200 B1200 B9600 B600 B4800 B50 B2400 B110
1788 =item Terminal interface values
1790 TCSADRAIN TCSANOW TCOON TCIOFLUSH TCOFLUSH TCION TCIFLUSH TCSAFLUSH TCIOFF TCOOFF
1792 =item c_cc field values
1794 VEOF VEOL VERASE VINTR VKILL VQUIT VSUSP VSTART VSTOP VMIN VTIME NCCS
1796 =item c_cflag field values
1798 CLOCAL CREAD CSIZE CS5 CS6 CS7 CS8 CSTOPB HUPCL PARENB PARODD
1800 =item c_iflag field values
1802 BRKINT ICRNL IGNBRK IGNCR IGNPAR INLCR INPCK ISTRIP IXOFF IXON PARMRK
1804 =item c_lflag field values
1806 ECHO ECHOE ECHOK ECHONL ICANON IEXTEN ISIG NOFLSH TOSTOP
1808 =item c_oflag field values
1814 =head1 PATHNAME CONSTANTS
1820 _PC_CHOWN_RESTRICTED _PC_LINK_MAX _PC_MAX_CANON _PC_MAX_INPUT _PC_NAME_MAX _PC_NO_TRUNC _PC_PATH_MAX _PC_PIPE_BUF _PC_VDISABLE
1824 =head1 POSIX CONSTANTS
1830 _POSIX_ARG_MAX _POSIX_CHILD_MAX _POSIX_CHOWN_RESTRICTED _POSIX_JOB_CONTROL _POSIX_LINK_MAX _POSIX_MAX_CANON _POSIX_MAX_INPUT _POSIX_NAME_MAX _POSIX_NGROUPS_MAX _POSIX_NO_TRUNC _POSIX_OPEN_MAX _POSIX_PATH_MAX _POSIX_PIPE_BUF _POSIX_SAVED_IDS _POSIX_SSIZE_MAX _POSIX_STREAM_MAX _POSIX_TZNAME_MAX _POSIX_VDISABLE _POSIX_VERSION
1834 =head1 SYSTEM CONFIGURATION
1840 _SC_ARG_MAX _SC_CHILD_MAX _SC_CLK_TCK _SC_JOB_CONTROL _SC_NGROUPS_MAX _SC_OPEN_MAX _SC_PAGESIZE _SC_SAVED_IDS _SC_STREAM_MAX _SC_TZNAME_MAX _SC_VERSION
1850 E2BIG EACCES EADDRINUSE EADDRNOTAVAIL EAFNOSUPPORT EAGAIN EALREADY EBADF
1851 EBUSY ECHILD ECONNABORTED ECONNREFUSED ECONNRESET EDEADLK EDESTADDRREQ
1852 EDOM EDQUOT EEXIST EFAULT EFBIG EHOSTDOWN EHOSTUNREACH EINPROGRESS EINTR
1853 EINVAL EIO EISCONN EISDIR ELOOP EMFILE EMLINK EMSGSIZE ENAMETOOLONG
1854 ENETDOWN ENETRESET ENETUNREACH ENFILE ENOBUFS ENODEV ENOENT ENOEXEC
1855 ENOLCK ENOMEM ENOPROTOOPT ENOSPC ENOSYS ENOTBLK ENOTCONN ENOTDIR
1856 ENOTEMPTY ENOTSOCK ENOTTY ENXIO EOPNOTSUPP EPERM EPFNOSUPPORT EPIPE
1857 EPROCLIM EPROTONOSUPPORT EPROTOTYPE ERANGE EREMOTE ERESTART EROFS
1858 ESHUTDOWN ESOCKTNOSUPPORT ESPIPE ESRCH ESTALE ETIMEDOUT ETOOMANYREFS
1859 ETXTBSY EUSERS EWOULDBLOCK EXDEV
1869 FD_CLOEXEC F_DUPFD F_GETFD F_GETFL F_GETLK F_OK F_RDLCK F_SETFD F_SETFL F_SETLK F_SETLKW F_UNLCK F_WRLCK O_ACCMODE O_APPEND O_CREAT O_EXCL O_NOCTTY O_NONBLOCK O_RDONLY O_RDWR O_TRUNC O_WRONLY
1879 DBL_DIG DBL_EPSILON DBL_MANT_DIG DBL_MAX DBL_MAX_10_EXP DBL_MAX_EXP DBL_MIN DBL_MIN_10_EXP DBL_MIN_EXP FLT_DIG FLT_EPSILON FLT_MANT_DIG FLT_MAX FLT_MAX_10_EXP FLT_MAX_EXP FLT_MIN FLT_MIN_10_EXP FLT_MIN_EXP FLT_RADIX FLT_ROUNDS LDBL_DIG LDBL_EPSILON LDBL_MANT_DIG LDBL_MAX LDBL_MAX_10_EXP LDBL_MAX_EXP LDBL_MIN LDBL_MIN_10_EXP LDBL_MIN_EXP
1889 ARG_MAX CHAR_BIT CHAR_MAX CHAR_MIN CHILD_MAX INT_MAX INT_MIN LINK_MAX LONG_MAX LONG_MIN MAX_CANON MAX_INPUT MB_LEN_MAX NAME_MAX NGROUPS_MAX OPEN_MAX PATH_MAX PIPE_BUF SCHAR_MAX SCHAR_MIN SHRT_MAX SHRT_MIN SSIZE_MAX STREAM_MAX TZNAME_MAX UCHAR_MAX UINT_MAX ULONG_MAX USHRT_MAX
1899 LC_ALL LC_COLLATE LC_CTYPE LC_MONETARY LC_NUMERIC LC_TIME
1919 SA_NOCLDSTOP SA_NOCLDWAIT SA_NODEFER SA_ONSTACK SA_RESETHAND SA_RESTART
1920 SA_SIGINFO SIGABRT SIGALRM SIGCHLD SIGCONT SIGFPE SIGHUP SIGILL SIGINT
1921 SIGKILL SIGPIPE SIGQUIT SIGSEGV SIGSTOP SIGTERM SIGTSTP SIGTTIN SIGTTOU
1922 SIGUSR1 SIGUSR2 SIG_BLOCK SIG_DFL SIG_ERR SIG_IGN SIG_SETMASK
1933 S_IRGRP S_IROTH S_IRUSR S_IRWXG S_IRWXO S_IRWXU S_ISGID S_ISUID S_IWGRP S_IWOTH S_IWUSR S_IXGRP S_IXOTH S_IXUSR
1937 S_ISBLK S_ISCHR S_ISDIR S_ISFIFO S_ISREG
1947 EXIT_FAILURE EXIT_SUCCESS MB_CUR_MAX RAND_MAX
1957 BUFSIZ EOF FILENAME_MAX L_ctermid L_cuserid L_tmpname TMP_MAX
1967 CLK_TCK CLOCKS_PER_SEC
1977 R_OK SEEK_CUR SEEK_END SEEK_SET STDIN_FILENO STDOUT_FILENO STDERR_FILENO W_OK X_OK
1993 Do not suspend the calling process until a child process
1994 changes state but instead return immediately.
1998 Catch stopped child processes.
2004 WIFEXITED WEXITSTATUS WIFSIGNALED WTERMSIG WIFSTOPPED WSTOPSIG
2010 WIFEXITED($?) returns true if the child process exited normally
2011 (C<exit()> or by falling off the end of C<main()>)
2015 WEXITSTATUS($?) returns the normal exit status of the child process
2016 (only meaningful if WIFEXITED($?) is true)
2020 WIFSIGNALED($?) returns true if the child process terminated because
2025 WTERMSIG($?) returns the signal the child process terminated for
2026 (only meaningful if WIFSIGNALED($?) is true)
2030 WIFSTOPPED($?) returns true if the child process is currently stopped
2031 (can happen only if you specified the WUNTRACED flag to waitpid())
2035 WSTOPSIG($?) returns the signal the child process was stopped for
2036 (only meaningful if WIFSTOPPED($?) is true)