MirOS Manual: POSIX(3p)


POSIX(3p)       Perl Programmers Reference Guide        POSIX(3p)

NAME

     POSIX - Perl interface to IEEE Std 1003.1

SYNOPSIS

         use POSIX;
         use POSIX qw(setsid);
         use POSIX qw(:errno_h :fcntl_h);

         printf "EINTR is %d\n", EINTR;

         $sess_id = POSIX::setsid();

         $fd = POSIX::open($path, O_CREAT|O_EXCL|O_WRONLY, 0644);
             # note: that's a filedescriptor, *NOT* a filehandle

DESCRIPTION

     The POSIX module permits you to access all (or nearly all)
     the standard POSIX 1003.1 identifiers.  Many of these iden-
     tifiers have been given Perl-ish interfaces.

     Everything is exported by default with the exception of any
     POSIX functions with the same name as a built-in Perl func-
     tion, such as "abs", "alarm", "rmdir", "write", etc.., which
     will be exported only if you ask for them explicitly.  This
     is an unfortunate backwards compatibility feature.  You can
     stop the exporting by saying "use POSIX ()" and then use the
     fully qualified names (ie. "POSIX::SEEK_END").

     This document gives a condensed list of the features avail-
     able in the POSIX module.  Consult your operating system's
     manpages for general information on most features.  Consult
     perlfunc for functions which are noted as being identical to
     Perl's builtin functions.

     The first section describes POSIX functions from the 1003.1
     specification. The second section describes some classes for
     signal objects, TTY objects, and other miscellaneous
     objects.  The remaining sections list various constants and
     macros in an organization which roughly follows IEEE Std
     1003.1b-1993.

NOTE

     The POSIX module is probably the most complex Perl module
     supplied with the standard distribution.  It incorporates
     autoloading, namespace games, and dynamic loading of code
     that's in Perl, C, or both.  It's a great source of wisdom.

CAVEATS

     A few functions are not implemented because they are C
     specific.  If you attempt to call these, they will print a
     message telling you that they aren't implemented, and sug-
     gest using the Perl equivalent should one exist.  For

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     example, trying to access the setjmp() call will elicit the
     message "setjmp() is C-specific: use eval {} instead".

     Furthermore, some evil vendors will claim 1003.1 compliance,
     but in fact are not so: they will not pass the PCTS (POSIX
     Compliance Test Suites). For example, one vendor may not
     define EDEADLK, or the semantics of the errno values set by
     open(2) might not be quite right.  Perl does not attempt to
     verify POSIX compliance.  That means you can currently suc-
     cessfully say "use POSIX",  and then later in your program
     you find that your vendor has been lax and there's no usable
     ICANON macro after all.  This could be construed to be a
     bug.

FUNCTIONS

     _exit   This is identical to the C function "_exit()".  It
             exits the program immediately which means among
             other things buffered I/O is not flushed.

             Note that when using threads and in Linux this is
             not a good way to exit a thread because in Linux
             processes and threads are kind of the same thing
             (Note: while this is the situation in early 2003
             there are projects under way to have threads with
             more POSIXly semantics in Linux). If you want not to
             return from a thread, detach the thread.

     abort   This is identical to the C function "abort()".  It
             terminates the process with a "SIGABRT" signal
             unless caught by a signal handler or if the handler
             does not return normally (it e.g.  does a
             "longjmp").

     abs     This is identical to Perl's builtin "abs()" func-
             tion, returning the absolute value of its numerical
             argument.

     access  Determines the accessibility of a file.

                     if( POSIX::access( "/", &POSIX::R_OK ) ){
                             print "have read permission\n";
                     }

             Returns "undef" on failure.  Note: do not use
             "access()" for security purposes.  Between the
             "access()" call and the operation you are preparing
             for the permissions might change: a classic race
             condition.

     acos    This is identical to the C function "acos()",
             returning the arcus cosine of its numerical argu-
             ment.  See also Math::Trig.

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     alarm   This is identical to Perl's builtin "alarm()" func-
             tion, either for arming or disarming the "SIGARLM"
             timer.

     asctime This is identical to the C function "asctime()".  It
             returns a string of the form

                     "Fri Jun  2 18:22:13 2000\n\0"

             and it is called thusly

                     $asctime = asctime($sec, $min, $hour, $mday, $mon, $year,
                                        $wday, $yday, $isdst);

             The $mon is zero-based: January equals 0.  The $year
             is 1900-based: 2001 equals 101.  The $wday, $yday,
             and $isdst default to zero (and the first two are
             usually ignored anyway).

     asin    This is identical to the C function "asin()",
             returning the arcus sine of its numerical argument.
             See also Math::Trig.

     assert  Unimplemented, but you can use "die" in perlfunc and
             the Carp module to achieve similar things.

     atan    This is identical to the C function "atan()",
             returning the arcus tangent of its numerical argu-
             ment.  See also Math::Trig.

     atan2   This is identical to Perl's builtin "atan2()" func-
             tion, returning the arcus tangent defined by its two
             numerical arguments, the y coordinate and the x
             coordinate.  See also Math::Trig.

     atexit  atexit() is C-specific: use "END {}" instead, see
             perlsub.

     atof    atof() is C-specific.  Perl converts strings to
             numbers transparently. If you need to force a scalar
             to a number, add a zero to it.

     atoi    atoi() is C-specific.  Perl converts strings to
             numbers transparently. If you need to force a scalar
             to a number, add a zero to it. If you need to have
             just the integer part, see "int" in perlfunc.

     atol    atol() is C-specific.  Perl converts strings to
             numbers transparently. If you need to force a scalar
             to a number, add a zero to it. If you need to have
             just the integer part, see "int" in perlfunc.

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     bsearch bsearch() not supplied.  For doing binary search on
             wordlists, see Search::Dict.

     calloc  calloc() is C-specific.  Perl does memory management
             transparently.

     ceil    This is identical to the C function "ceil()",
             returning the smallest integer value greater than or
             equal to the given numerical argument.

     chdir   This is identical to Perl's builtin "chdir()" func-
             tion, allowing one to change the working (default)
             directory, see "chdir" in perlfunc.

     chmod   This is identical to Perl's builtin "chmod()" func-
             tion, allowing one to change file and directory per-
             missions, see "chmod" in perlfunc.

     chown   This is identical to Perl's builtin "chown()" func-
             tion, allowing one to change file and directory own-
             ers and groups, see "chown" in perlfunc.

     clearerr
             Use the method "IO::Handle::clearerr()" instead, to
             reset the error state (if any) and EOF state (if
             any) of the given stream.

     clock   This is identical to the C function "clock()",
             returning the amount of spent processor time in
             microseconds.

     close   Close the file.  This uses file descriptors such as
             those obtained by calling "POSIX::open".

                     $fd = POSIX::open( "foo", &POSIX::O_RDONLY );
                     POSIX::close( $fd );

             Returns "undef" on failure.

             See also "close" in perlfunc.

     closedir
             This is identical to Perl's builtin "closedir()"
             function for closing a directory handle, see
             "closedir" in perlfunc.

     cos     This is identical to Perl's builtin "cos()" func-
             tion, for returning the cosine of its numerical
             argument, see "cos" in perlfunc. See also
             Math::Trig.

     cosh    This is identical to the C function "cosh()", for

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             returning the hyperbolic cosine of its numeric argu-
             ment.  See also Math::Trig.

     creat   Create a new file.  This returns a file descriptor
             like the ones returned by "POSIX::open".  Use
             "POSIX::close" to close the file.

                     $fd = POSIX::creat( "foo", 0611 );
                     POSIX::close( $fd );

             See also "sysopen" in perlfunc and its "O_CREAT"
             flag.

     ctermid Generates the path name for the controlling termi-
             nal.

                     $path = POSIX::ctermid();

     ctime   This is identical to the C function "ctime()" and
             equivalent to "asctime(localtime(...))", see "asc-
             time" and "localtime".

     cuserid Get the login name of the owner of the current pro-
             cess.

                     $name = POSIX::cuserid();

     difftime
             This is identical to the C function "difftime()",
             for returning the time difference (in seconds)
             between two times (as returned by "time()"), see
             "time".

     div     div() is C-specific, use "int" in perlfunc on the
             usual "/" division and the modulus "%".

     dup     This is similar to the C function "dup()", for
             duplicating a file descriptor.

             This uses file descriptors such as those obtained by
             calling "POSIX::open".

             Returns "undef" on failure.

     dup2    This is similar to the C function "dup2()", for
             duplicating a file descriptor to an another known
             file descriptor.

             This uses file descriptors such as those obtained by
             calling "POSIX::open".

             Returns "undef" on failure.

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     errno   Returns the value of errno.

                     $errno = POSIX::errno();

             This identical to the numerical values of the $!,
             see "$ERRNO" in perlvar.

     execl   execl() is C-specific, see "exec" in perlfunc.

     execle  execle() is C-specific, see "exec" in perlfunc.

     execlp  execlp() is C-specific, see "exec" in perlfunc.

     execv   execv() is C-specific, see "exec" in perlfunc.

     execve  execve() is C-specific, see "exec" in perlfunc.

     execvp  execvp() is C-specific, see "exec" in perlfunc.

     exit    This is identical to Perl's builtin "exit()" func-
             tion for exiting the program, see "exit" in perl-
             func.

     exp     This is identical to Perl's builtin "exp()" function
             for returning the exponent (e-based) of the numeri-
             cal argument, see "exp" in perlfunc.

     fabs    This is identical to Perl's builtin "abs()" function
             for returning the absolute value of the numerical
             argument, see "abs" in perlfunc.

     fclose  Use method "IO::Handle::close()" instead, or see
             "close" in perlfunc.

     fcntl   This is identical to Perl's builtin "fcntl()" func-
             tion, see "fcntl" in perlfunc.

     fdopen  Use method "IO::Handle::new_from_fd()" instead, or
             see "open" in perlfunc.

     feof    Use method "IO::Handle::eof()" instead, or see "eof"
             in perlfunc.

     ferror  Use method "IO::Handle::error()" instead.

     fflush  Use method "IO::Handle::flush()" instead. See also
             "$OUTPUT_AUTOFLUSH" in perlvar.

     fgetc   Use method "IO::Handle::getc()" instead, or see
             "read" in perlfunc.

     fgetpos Use method "IO::Seekable::getpos()" instead, or see

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             "seek" in L.

     fgets   Use method "IO::Handle::gets()" instead.  Similar to
             <>, also known as "readline" in perlfunc.

     fileno  Use method "IO::Handle::fileno()" instead, or see
             "fileno" in perlfunc.

     floor   This is identical to the C function "floor()",
             returning the largest integer value less than or
             equal to the numerical argument.

     fmod    This is identical to the C function "fmod()".

                     $r = fmod($x, $y);

             It returns the remainder "$r = $x - $n*$y", where
             "$n = trunc($x/$y)". The $r has the same sign as $x
             and magnitude (absolute value) less than the magni-
             tude of $y.

     fopen   Use method "IO::File::open()" instead, or see "open"
             in perlfunc.

     fork    This is identical to Perl's builtin "fork()" func-
             tion for duplicating the current process, see "fork"
             in perlfunc and perlfork if you are in Windows.

     fpathconf
             Retrieves the value of a configurable limit on a
             file or directory.  This uses file descriptors such
             as those obtained by calling "POSIX::open".

             The following will determine the maximum length of
             the longest allowable pathname on the filesystem
             which holds "/var/foo".

                     $fd = POSIX::open( "/var/foo", &POSIX::O_RDONLY );
                     $path_max = POSIX::fpathconf( $fd, &POSIX::_PC_PATH_MAX );

             Returns "undef" on failure.

     fprintf fprintf() is C-specific, see "printf" in perlfunc
             instead.

     fputc   fputc() is C-specific, see "print" in perlfunc
             instead.

     fputs   fputs() is C-specific, see "print" in perlfunc
             instead.

     fread   fread() is C-specific, see "read" in perlfunc

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             instead.

     free    free() is C-specific.  Perl does memory management
             transparently.

     freopen freopen() is C-specific, see "open" in perlfunc
             instead.

     frexp   Return the mantissa and exponent of a floating-point
             number.

                     ($mantissa, $exponent) = POSIX::frexp( 1.234e56 );

     fscanf  fscanf() is C-specific, use <> and regular expres-
             sions instead.

     fseek   Use method "IO::Seekable::seek()" instead, or see
             "seek" in perlfunc.

     fsetpos Use method "IO::Seekable::setpos()" instead, or seek
             "seek" in perlfunc.

     fstat   Get file status.  This uses file descriptors such as
             those obtained by calling "POSIX::open".  The data
             returned is identical to the data from Perl's buil-
             tin "stat" function.

                     $fd = POSIX::open( "foo", &POSIX::O_RDONLY );
                     @stats = POSIX::fstat( $fd );

     fsync   Use method "IO::Handle::sync()" instead.

     ftell   Use method "IO::Seekable::tell()" instead, or see
             "tell" in perlfunc.

     fwrite  fwrite() is C-specific, see "print" in perlfunc
             instead.

     getc    This is identical to Perl's builtin "getc()" func-
             tion, see "getc" in perlfunc.

     getchar Returns one character from STDIN.  Identical to
             Perl's "getc()", see "getc" in perlfunc.

     getcwd  Returns the name of the current working directory.
             See also Cwd.

     getegid Returns the effective group identifier.  Similar to
             Perl' s builtin variable $(, see "$EGID" in perlvar.

     getenv  Returns the value of the specified environment vari-
             able. The same information is available through the

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             %ENV array.

     geteuid Returns the effective user identifier.  Identical to
             Perl's builtin $> variable, see "$EUID" in perlvar.

     getgid  Returns the user's real group identifier.  Similar
             to Perl's builtin variable $), see "$GID" in perl-
             var.

     getgrgid
             This is identical to Perl's builtin "getgrgid()"
             function for returning group entries by group iden-
             tifiers, see "getgrgid" in perlfunc.

     getgrnam
             This is identical to Perl's builtin "getgrnam()"
             function for returning group entries by group names,
             see "getgrnam" in perlfunc.

     getgroups
             Returns the ids of the user's supplementary groups.
             Similar to Perl's builtin variable $), see "$GID" in
             perlvar.

     getlogin
             This is identical to Perl's builtin "getlogin()"
             function for returning the user name associated with
             the current session, see "getlogin" in perlfunc.

     getpgrp This is identical to Perl's builtin "getpgrp()"
             function for returning the process group identifier
             of the current process, see "getpgrp" in perlfunc.

     getpid  Returns the process identifier.  Identical to Perl's
             builtin variable $$, see "$PID" in perlvar.

     getppid This is identical to Perl's builtin "getppid()"
             function for returning the process identifier of the
             parent process of the current process , see
             "getppid" in perlfunc.

     getpwnam
             This is identical to Perl's builtin "getpwnam()"
             function for returning user entries by user names,
             see "getpwnam" in perlfunc.

     getpwuid
             This is identical to Perl's builtin "getpwuid()"
             function for returning user entries by user identif-
             iers, see "getpwuid" in perlfunc.

     gets    Returns one line from "STDIN", similar to <>, also

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             known as the "readline()" function, see "readline"
             in perlfunc.

             NOTE: if you have C programs that still use
             "gets()", be very afraid.  The "gets()" function is
             a source of endless grief because it has no buffer
             overrun checks.  It should never be used.  The
             "fgets()" function should be preferred instead.

     getuid  Returns the user's identifier.  Identical to Perl's
             builtin $< variable, see "$UID" in perlvar.

     gmtime  This is identical to Perl's builtin "gmtime()" func-
             tion for converting seconds since the epoch to a
             date in Greenwich Mean Time, see "gmtime" in perl-
             func.

     isalnum This is identical to the C function, except that it
             can apply to a single character or to a whole
             string.  Note that locale settings may affect what
             characters are considered "isalnum".  Does not work
             on Unicode characters code point 256 or higher.
             Consider using regular expressions and the
             "/[[:alnum:]]/" construct instead, or possibly the
             "/\w/" construct.

     isalpha This is identical to the C function, except that it
             can apply to a single character or to a whole
             string.  Note that locale settings may affect what
             characters are considered "isalpha".  Does not work
             on Unicode characters code point 256 or higher.
             Consider using regular expressions and the
             "/[[:alpha:]]/" construct instead.

     isatty  Returns a boolean indicating whether the specified
             filehandle is connected to a tty.  Similar to the
             "-t" operator, see "-X" in perlfunc.

     iscntrl This is identical to the C function, except that it
             can apply to a single character or to a whole
             string.  Note that locale settings may affect what
             characters are considered "iscntrl".  Does not work
             on Unicode characters code point 256 or higher.
             Consider using regular expressions and the
             "/[[:cntrl:]]/" construct instead.

     isdigit This is identical to the C function, except that it
             can apply to a single character or to a whole
             string.  Note that locale settings may affect what
             characters are considered "isdigit" (unlikely, but
             still possible). Does not work on Unicode characters
             code point 256 or higher.  Consider using regular

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             expressions and the "/[[:digit:]]/" construct
             instead, or the "/\d/" construct.

     isgraph This is identical to the C function, except that it
             can apply to a single character or to a whole
             string.  Note that locale settings may affect what
             characters are considered "isgraph".  Does not work
             on Unicode characters code point 256 or higher.
             Consider using regular expressions and the
             "/[[:graph:]]/" construct instead.

     islower This is identical to the C function, except that it
             can apply to a single character or to a whole
             string.  Note that locale settings may affect what
             characters are considered "islower".  Does not work
             on Unicode characters code point 256 or higher.
             Consider using regular expressions and the
             "/[[:lower:]]/" construct instead.  Do not use
             "/[a-z]/".

     isprint This is identical to the C function, except that it
             can apply to a single character or to a whole
             string.  Note that locale settings may affect what
             characters are considered "isprint".  Does not work
             on Unicode characters code point 256 or higher.
             Consider using regular expressions and the
             "/[[:print:]]/" construct instead.

     ispunct This is identical to the C function, except that it
             can apply to a single character or to a whole
             string.  Note that locale settings may affect what
             characters are considered "ispunct".  Does not work
             on Unicode characters code point 256 or higher.
             Consider using regular expressions and the
             "/[[:punct:]]/" construct instead.

     isspace This is identical to the C function, except that it
             can apply to a single character or to a whole
             string.  Note that locale settings may affect what
             characters are considered "isspace".  Does not work
             on Unicode characters code point 256 or higher.
             Consider using regular expressions and the
             "/[[:space:]]/" construct instead, or the "/\s/"
             construct.  (Note that "/\s/" and "/[[:space:]]/"
             are slightly different in that "/[[:space:]]/" can
             normally match a vertical tab, while "/\s/" does
             not.)

     isupper This is identical to the C function, except that it
             can apply to a single character or to a whole
             string.  Note that locale settings may affect what
             characters are considered "isupper".  Does not work

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             on Unicode characters code point 256 or higher.
             Consider using regular expressions and the
             "/[[:upper:]]/" construct instead.  Do not use
             "/[A-Z]/".

     isxdigit
             This is identical to the C function, except that it
             can apply to a single character or to a whole
             string.  Note that locale settings may affect what
             characters are considered "isxdigit" (unlikely, but
             still possible). Does not work on Unicode characters
             code point 256 or higher. Consider using regular
             expressions and the "/[[:xdigit:]]/" construct
             instead, or simply "/[0-9a-f]/i".

     kill    This is identical to Perl's builtin "kill()" func-
             tion for sending signals to processes (often to ter-
             minate them), see "kill" in perlfunc.

     labs    (For returning absolute values of long integers.)
             labs() is C-specific, see "abs" in perlfunc instead.

     ldexp   This is identical to the C function "ldexp()" for
             multiplying floating point numbers with powers of
             two.

                     $x_quadrupled = POSIX::ldexp($x, 2);

     ldiv    (For computing dividends of long integers.) ldiv()
             is C-specific, use "/" and "int()" instead.

     link    This is identical to Perl's builtin "link()" func-
             tion for creating hard links into files, see "link"
             in perlfunc.

     localeconv
             Get numeric formatting information.  Returns a
             reference to a hash containing the current locale
             formatting values.

             Here is how to query the database for the de
             (Deutsch or German) locale.

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                     $loc = POSIX::setlocale( &POSIX::LC_ALL, "de" );
                     print "Locale = $loc\n";
                     $lconv = POSIX::localeconv();
                     print "decimal_point    = ", $lconv->{decimal_point},   "\n";
                     print "thousands_sep    = ", $lconv->{thousands_sep},   "\n";
                     print "grouping = ", $lconv->{grouping},        "\n";
                     print "int_curr_symbol  = ", $lconv->{int_curr_symbol}, "\n";
                     print "currency_symbol  = ", $lconv->{currency_symbol}, "\n";
                     print "mon_decimal_point = ", $lconv->{mon_decimal_point}, "\n";
                     print "mon_thousands_sep = ", $lconv->{mon_thousands_sep}, "\n";
                     print "mon_grouping     = ", $lconv->{mon_grouping},    "\n";
                     print "positive_sign    = ", $lconv->{positive_sign},   "\n";
                     print "negative_sign    = ", $lconv->{negative_sign},   "\n";
                     print "int_frac_digits  = ", $lconv->{int_frac_digits}, "\n";
                     print "frac_digits      = ", $lconv->{frac_digits},     "\n";
                     print "p_cs_precedes    = ", $lconv->{p_cs_precedes},   "\n";
                     print "p_sep_by_space   = ", $lconv->{p_sep_by_space},  "\n";
                     print "n_cs_precedes    = ", $lconv->{n_cs_precedes},   "\n";
                     print "n_sep_by_space   = ", $lconv->{n_sep_by_space},  "\n";
                     print "p_sign_posn      = ", $lconv->{p_sign_posn},     "\n";
                     print "n_sign_posn      = ", $lconv->{n_sign_posn},     "\n";

     localtime
             This is identical to Perl's builtin "localtime()"
             function for converting seconds since the epoch to a
             date see "localtime" in perlfunc.

     log     This is identical to Perl's builtin "log()" func-
             tion, returning the natural (e-based) logarithm of
             the numerical argument, see "log" in perlfunc.

     log10   This is identical to the C function "log10()",
             returning the 10-base logarithm of the numerical
             argument. You can also use

                 sub log10 { log($_[0]) / log(10) }

             or

                 sub log10 { log($_[0]) / 2.30258509299405 }

             or

                 sub log10 { log($_[0]) * 0.434294481903252 }

     longjmp longjmp() is C-specific: use "die" in perlfunc
             instead.

     lseek   Move the file's read/write position.  This uses file
             descriptors such as those obtained by calling
             "POSIX::open".

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                     $fd = POSIX::open( "foo", &POSIX::O_RDONLY );
                     $off_t = POSIX::lseek( $fd, 0, &POSIX::SEEK_SET );

             Returns "undef" on failure.

     malloc  malloc() is C-specific.  Perl does memory management
             transparently.

     mblen   This is identical to the C function "mblen()". Perl
             does not have any support for the wide and multibyte
             characters of the C standards, so this might be a
             rather useless function.

     mbstowcs
             This is identical to the C function "mbstowcs()".
             Perl does not have any support for the wide and mul-
             tibyte characters of the C standards, so this might
             be a rather useless function.

     mbtowc  This is identical to the C function "mbtowc()". Perl
             does not have any support for the wide and multibyte
             characters of the C standards, so this might be a
             rather useless function.

     memchr  memchr() is C-specific, see "index" in perlfunc
             instead.

     memcmp  memcmp() is C-specific, use "eq" instead, see per-
             lop.

     memcpy  memcpy() is C-specific, use "=", see perlop, or see
             "substr" in perlfunc.

     memmove memmove() is C-specific, use "=", see perlop, or see
             "substr" in perlfunc.

     memset  memset() is C-specific, use "x" instead, see perlop.

     mkdir   This is identical to Perl's builtin "mkdir()" func-
             tion for creating directories, see "mkdir" in perl-
             func.

     mkfifo  This is similar to the C function "mkfifo()" for
             creating FIFO special files.

                     if (mkfifo($path, $mode)) { ....

             Returns "undef" on failure.  The $mode is similar to
             the mode of "mkdir()", see "mkdir" in perlfunc.

     mktime  Convert date/time info to a calendar time.

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             Synopsis:

                     mktime(sec, min, hour, mday, mon, year, wday = 0, yday = 0, isdst = 0)

             The month ("mon"), weekday ("wday"), and yearday
             ("yday") begin at zero. I.e. January is 0, not 1;
             Sunday is 0, not 1; January 1st is 0, not 1.  The
             year ("year") is given in years since 1900.  I.e.
             The year 1995 is 95; the year 2001 is 101.  Consult
             your system's "mktime()" manpage for details about
             these and the other arguments.

             Calendar time for December 12, 1995, at 10:30 am.

                     $time_t = POSIX::mktime( 0, 30, 10, 12, 11, 95 );
                     print "Date = ", POSIX::ctime($time_t);

             Returns "undef" on failure.

     modf    Return the integral and fractional parts of a
             floating-point number.

                     ($fractional, $integral) = POSIX::modf( 3.14 );

     nice    This is similar to the C function "nice()", for
             changing the scheduling preference of the current
             process.  Positive arguments mean more polite pro-
             cess, negative values more needy process.  Normal
             user processes can only be more polite.

             Returns "undef" on failure.

     offsetof
             offsetof() is C-specific, you probably want to see
             "pack" in perlfunc instead.

     open    Open a file for reading for writing.  This returns
             file descriptors, not Perl filehandles.  Use
             "POSIX::close" to close the file.

             Open a file read-only with mode 0666.

                     $fd = POSIX::open( "foo" );

             Open a file for read and write.

                     $fd = POSIX::open( "foo", &POSIX::O_RDWR );

             Open a file for write, with truncation.

                     $fd = POSIX::open( "foo", &POSIX::O_WRONLY | &POSIX::O_TRUNC );

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             Create a new file with mode 0640.  Set up the file
             for writing.

                     $fd = POSIX::open( "foo", &POSIX::O_CREAT | &POSIX::O_WRONLY, 0640 );

             Returns "undef" on failure.

             See also "sysopen" in perlfunc.

     opendir Open a directory for reading.

                     $dir = POSIX::opendir( "/var" );
                     @files = POSIX::readdir( $dir );
                     POSIX::closedir( $dir );

             Returns "undef" on failure.

     pathconf
             Retrieves the value of a configurable limit on a
             file or directory.

             The following will determine the maximum length of
             the longest allowable pathname on the filesystem
             which holds "/var".

                     $path_max = POSIX::pathconf( "/var", &POSIX::_PC_PATH_MAX );

             Returns "undef" on failure.

     pause   This is similar to the C function "pause()", which
             suspends the execution of the current process until
             a signal is received.

             Returns "undef" on failure.

     perror  This is identical to the C function "perror()",
             which outputs to the standard error stream the
             specified message followed by ": " and the current
             error string.  Use the "warn()" function and the $!
             variable instead, see "warn" in perlfunc and
             "$ERRNO" in perlvar.

     pipe    Create an interprocess channel.  This returns file
             descriptors like those returned by "POSIX::open".

                     my ($read, $write) = POSIX::pipe();
                     POSIX::write( $write, "hello", 5 );
                     POSIX::read( $read, $buf, 5 );

             See also "pipe" in perlfunc.

     pow     Computes $x raised to the power $exponent.

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                     $ret = POSIX::pow( $x, $exponent );

             You can also use the "**" operator, see perlop.

     printf  Formats and prints the specified arguments to
             STDOUT. See also "printf" in perlfunc.

     putc    putc() is C-specific, see "print" in perlfunc
             instead.

     putchar putchar() is C-specific, see "print" in perlfunc
             instead.

     puts    puts() is C-specific, see "print" in perlfunc
             instead.

     qsort   qsort() is C-specific, see "sort" in perlfunc
             instead.

     raise   Sends the specified signal to the current process.
             See also "kill" in perlfunc and the $$ in "$PID" in
             perlvar.

     rand    "rand()" is non-portable, see "rand" in perlfunc
             instead.

     read    Read from a file.  This uses file descriptors such
             as those obtained by calling "POSIX::open".  If the
             buffer $buf is not large enough for the read then
             Perl will extend it to make room for the request.

                     $fd = POSIX::open( "foo", &POSIX::O_RDONLY );
                     $bytes = POSIX::read( $fd, $buf, 3 );

             Returns "undef" on failure.

             See also "sysread" in perlfunc.

     readdir This is identical to Perl's builtin "readdir()"
             function for reading directory entries, see "read-
             dir" in perlfunc.

     realloc realloc() is C-specific.  Perl does memory manage-
             ment transparently.

     remove  This is identical to Perl's builtin "unlink()" func-
             tion for removing files, see "unlink" in perlfunc.

     rename  This is identical to Perl's builtin "rename()" func-
             tion for renaming files, see "rename" in perlfunc.

     rewind  Seeks to the beginning of the file.

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     rewinddir
             This is identical to Perl's builtin "rewinddir()"
             function for rewinding directory entry streams, see
             "rewinddir" in perlfunc.

     rmdir   This is identical to Perl's builtin "rmdir()" func-
             tion for removing (empty) directories, see "rmdir"
             in perlfunc.

     scanf   scanf() is C-specific, use <> and regular expres-
             sions instead, see perlre.

     setgid  Sets the real group identifier and the effective
             group identifier for this process.  Similar to
             assigning a value to the Perl's builtin $) variable,
             see "$GID" in perlvar, except that the latter will
             change only the real user identifier, and that the
             setgid() uses only a single numeric argument, as
             opposed to a space-separated list of numbers.

     setjmp  "setjmp()" is C-specific: use "eval {}" instead, see
             "eval" in perlfunc.

     setlocale
             Modifies and queries program's locale.  The follow-
             ing examples assume

                     use POSIX qw(setlocale LC_ALL LC_CTYPE);

             has been issued.

             The following will set the traditional UNIX system
             locale behavior (the second argument "C").

                     $loc = setlocale( LC_ALL, "C" );

             The following will query the current LC_CTYPE
             category.  (No second argument means 'query'.)

                     $loc = setlocale( LC_CTYPE );

             The following will set the LC_CTYPE behaviour
             according to the locale environment variables (the
             second argument ""). Please see your systems setlocale(3)
             documentation for the locale environment
             variables' meaning or consult perllocale.

                     $loc = setlocale( LC_CTYPE, "" );

             The following will set the LC_COLLATE behaviour to
             Argentinian Spanish. NOTE: The naming and availabil-
             ity of locales depends on your operating system.

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             Please consult perllocale for how to find out which
             locales are available in your system.

                     $loc = setlocale( LC_ALL, "es_AR.ISO8859-1" );

     setpgid This is similar to the C function "setpgid()" for
             setting the process group identifier of the current
             process.

             Returns "undef" on failure.

     setsid  This is identical to the C function "setsid()" for
             setting the session identifier of the current pro-
             cess.

     setuid  Sets the real user identifier and the effective user
             identifier for this process.  Similar to assigning a
             value to the Perl's builtin $< variable, see "$UID"
             in perlvar, except that the latter will change only
             the real user identifier.

     sigaction
             Detailed signal management.  This uses
             "POSIX::SigAction" objects for the "action" and
             "oldaction" arguments.  Consult your system's
             "sigaction" manpage for details.

             Synopsis:

                     sigaction(signal, action, oldaction = 0)

             Returns "undef" on failure.  The "signal" must be a
             number (like SIGHUP), not a string (like "SIGHUP"),
             though Perl does try hard to understand you.

     siglongjmp
             siglongjmp() is C-specific: use "die" in perlfunc
             instead.

     sigpending
             Examine signals that are blocked and pending.  This
             uses "POSIX::SigSet" objects for the "sigset" argu-
             ment.  Consult your system's "sigpending" manpage
             for details.

             Synopsis:

                     sigpending(sigset)

             Returns "undef" on failure.

     sigprocmask

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             Change and/or examine calling process's signal mask.
             This uses "POSIX::SigSet" objects for the "sigset"
             and "oldsigset" arguments. Consult your system's
             "sigprocmask" manpage for details.

             Synopsis:

                     sigprocmask(how, sigset, oldsigset = 0)

             Returns "undef" on failure.

     sigsetjmp
             "sigsetjmp()" is C-specific: use "eval {}" instead,
             see "eval" in perlfunc.

     sigsuspend
             Install a signal mask and suspend process until sig-
             nal arrives.  This uses "POSIX::SigSet" objects for
             the "signal_mask" argument.  Consult your system's
             "sigsuspend" manpage for details.

             Synopsis:

                     sigsuspend(signal_mask)

             Returns "undef" on failure.

     sin     This is identical to Perl's builtin "sin()" function
             for returning the sine of the numerical argument,
             see "sin" in perlfunc.  See also Math::Trig.

     sinh    This is identical to the C function "sinh()" for
             returning the hyperbolic sine of the numerical argu-
             ment. See also Math::Trig.

     sleep   This is functionally identical to Perl's builtin
             "sleep()" function for suspending the execution of
             the current for process for certain number of
             seconds, see "sleep" in perlfunc.  There is one sig-
             nificant difference, however: "POSIX::sleep()"
             returns the number of unslept seconds, while the
             "CORE::sleep()" returns the number of slept seconds.

     sprintf This is similar to Perl's builtin "sprintf()" func-
             tion for returning a string that has the arguments
             formatted as requested, see "sprintf" in perlfunc.

     sqrt    This is identical to Perl's builtin "sqrt()" func-
             tion. for returning the square root of the numerical
             argument, see "sqrt" in perlfunc.

     srand   Give a seed the pseudorandom number generator, see

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             "srand" in perlfunc.

     sscanf  sscanf() is C-specific, use regular expressions
             instead, see perlre.

     stat    This is identical to Perl's builtin "stat()" func-
             tion for returning information about files and
             directories.

     strcat  strcat() is C-specific, use ".=" instead, see per-
             lop.

     strchr  strchr() is C-specific, see "index" in perlfunc
             instead.

     strcmp  strcmp() is C-specific, use "eq" or "cmp" instead,
             see perlop.

     strcoll This is identical to the C function "strcoll()" for
             collating (comparing) strings transformed using the
             "strxfrm()" function.  Not really needed since Perl
             can do this transparently, see perllocale.

     strcpy  strcpy() is C-specific, use "=" instead, see perlop.

     strcspn strcspn() is C-specific, use regular expressions
             instead, see perlre.

     strerror
             Returns the error string for the specified errno.
             Identical to the string form of the $!, see "$ERRNO"
             in perlvar.

     strftime
             Convert date and time information to string.
             Returns the string.

             Synopsis:

                     strftime(fmt, sec, min, hour, mday, mon, year, wday = -1, yday = -1, isdst = -1)

             The month ("mon"), weekday ("wday"), and yearday
             ("yday") begin at zero. I.e. January is 0, not 1;
             Sunday is 0, not 1; January 1st is 0, not 1.  The
             year ("year") is given in years since 1900.  I.e.,
             the year 1995 is 95; the year 2001 is 101.  Consult
             your system's "strftime()" manpage for details about
             these and the other arguments.

             If you want your code to be portable, your format
             ("fmt") argument should use only the conversion
             specifiers defined by the ANSI C standard (C89, to

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             play safe).  These are "aAbBcdHIjmMpSUwWxXyYZ%". But
             even then, the results of some of the conversion
             specifiers are non-portable.  For example, the
             specifiers "aAbBcpZ" change according to the locale
             settings of the user, and both how to set locales
             (the locale names) and what output to expect are
             non-standard. The specifier "c" changes according to
             the timezone settings of the user and the timezone
             computation rules of the operating system. The "Z"
             specifier is notoriously unportable since the names
             of timezones are non-standard. Sticking to the
             numeric specifiers is the safest route.

             The given arguments are made consistent as though by
             calling "mktime()" before calling your system's
             "strftime()" function, except that the "isdst" value
             is not affected.

             The string for Tuesday, December 12, 1995.

                     $str = POSIX::strftime( "%A, %B %d, %Y", 0, 0, 0, 12, 11, 95, 2 );
                     print "$str\n";

     strlen  strlen() is C-specific, use "length()" instead, see
             "length" in perlfunc.

     strncat strncat() is C-specific, use ".=" instead, see per-
             lop.

     strncmp strncmp() is C-specific, use "eq" instead, see per-
             lop.

     strncpy strncpy() is C-specific, use "=" instead, see per-
             lop.

     strpbrk strpbrk() is C-specific, use regular expressions
             instead, see perlre.

     strrchr strrchr() is C-specific, see "rindex" in perlfunc
             instead.

     strspn  strspn() is C-specific, use regular expressions
             instead, see perlre.

     strstr  This is identical to Perl's builtin "index()" func-
             tion, see "index" in perlfunc.

     strtod  String to double translation. Returns the parsed
             number and the number of characters in the unparsed
             portion of the string.  Truly POSIX-compliant sys-
             tems set $! ($ERRNO) to indicate a translation
             error, so clear $! before calling strtod.  However,

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             non-POSIX systems may not check for overflow, and
             therefore will never set $!.

             strtod should respect any POSIX setlocale() set-
             tings.

             To parse a string $str as a floating point number
             use

                 $! = 0;
                 ($num, $n_unparsed) = POSIX::strtod($str);

             The second returned item and $! can be used to check
             for valid input:

                 if (($str eq '') || ($n_unparsed != 0) || $!) {
                     die "Non-numeric input $str" . ($! ? ": $!\n" : "\n");
                 }

             When called in a scalar context strtod returns the
             parsed number.

     strtok  strtok() is C-specific, use regular expressions
             instead, see perlre, or "split" in perlfunc.

     strtol  String to (long) integer translation.  Returns the
             parsed number and the number of characters in the
             unparsed portion of the string.  Truly POSIX-
             compliant systems set $! ($ERRNO) to indicate a
             translation error, so clear $! before calling
             strtol.  However, non-POSIX systems may not check
             for overflow, and therefore will never set $!.

             strtol should respect any POSIX setlocale() set-
             tings.

             To parse a string $str as a number in some base
             $base use

                 $! = 0;
                 ($num, $n_unparsed) = POSIX::strtol($str, $base);

             The base should be zero or between 2 and 36,
             inclusive.  When the base is zero or omitted strtol
             will use the string itself to determine the base: a
             leading "0x" or "0X" means hexadecimal; a leading
             "0" means octal; any other leading characters mean
             decimal.  Thus, "1234" is parsed as a decimal
             number, "01234" as an octal number, and "0x1234" as
             a hexadecimal number.

             The second returned item and $! can be used to check

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             for valid input:

                 if (($str eq '') || ($n_unparsed != 0) || !$!) {
                     die "Non-numeric input $str" . $! ? ": $!\n" : "\n";
                 }

             When called in a scalar context strtol returns the
             parsed number.

     strtoul String to unsigned (long) integer translation.
             strtoul() is identical to strtol() except that
             strtoul() only parses unsigned integers.  See
             "strtol" for details.

             Note: Some vendors supply strtod() and strtol() but
             not strtoul(). Other vendors that do supply
             strtoul() parse "-1" as a valid value.

     strxfrm String transformation.  Returns the transformed
             string.

                     $dst = POSIX::strxfrm( $src );

             Used in conjunction with the "strcoll()" function,
             see "strcoll".

             Not really needed since Perl can do this tran-
             sparently, see perllocale.

     sysconf Retrieves values of system configurable variables.

             The following will get the machine's clock speed.

                     $clock_ticks = POSIX::sysconf( &POSIX::_SC_CLK_TCK );

             Returns "undef" on failure.

     system  This is identical to Perl's builtin "system()" func-
             tion, see "system" in perlfunc.

     tan     This is identical to the C function "tan()", return-
             ing the tangent of the numerical argument.  See also
             Math::Trig.

     tanh    This is identical to the C function "tanh()",
             returning the hyperbolic tangent of the numerical
             argument.   See also Math::Trig.

     tcdrain This is similar to the C function "tcdrain()" for
             draining the output queue of its argument stream.

             Returns "undef" on failure.

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     tcflow  This is similar to the C function "tcflow()" for
             controlling the flow of its argument stream.

             Returns "undef" on failure.

     tcflush This is similar to the C function "tcflush()" for
             flushing the I/O buffers of its argument stream.

             Returns "undef" on failure.

     tcgetpgrp
             This is identical to the C function "tcgetpgrp()"
             for returning the process group identifier of the
             foreground process group of the controlling termi-
             nal.

     tcsendbreak
             This is similar to the C function "tcsendbreak()"
             for sending a break on its argument stream.

             Returns "undef" on failure.

     tcsetpgrp
             This is similar to the C function "tcsetpgrp()" for
             setting the process group identifier of the fore-
             ground process group of the controlling terminal.

             Returns "undef" on failure.

     time    This is identical to Perl's builtin "time()" func-
             tion for returning the number of seconds since the
             epoch (whatever it is for the system), see "time" in
             perlfunc.

     times   The times() function returns elapsed realtime since
             some point in the past (such as system startup),
             user and system times for this process, and user and
             system times used by child processes.  All times are
             returned in clock ticks.

                 ($realtime, $user, $system, $cuser, $csystem) = POSIX::times();

             Note: Perl's builtin "times()" function returns four
             values, measured in seconds.

     tmpfile Use method "IO::File::new_tmpfile()" instead, or see
             File::Temp.

     tmpnam  Returns a name for a temporary file.

                     $tmpfile = POSIX::tmpnam();

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             For security reasons, which are probably detailed in
             your system's documentation for the C library
             tmpnam() function, this interface should not be
             used; instead see File::Temp.

     tolower This is identical to the C function, except that it
             can apply to a single character or to a whole
             string.  Consider using the "lc()" function, see
             "lc" in perlfunc, or the equivalent "\L" operator
             inside doublequotish strings.

     toupper This is identical to the C function, except that it
             can apply to a single character or to a whole
             string.  Consider using the "uc()" function, see
             "uc" in perlfunc, or the equivalent "\U" operator
             inside doublequotish strings.

     ttyname This is identical to the C function "ttyname()" for
             returning the name of the current terminal.

     tzname  Retrieves the time conversion information from the
             "tzname" variable.

                     POSIX::tzset();
                     ($std, $dst) = POSIX::tzname();

     tzset   This is identical to the C function "tzset()" for
             setting the current timezone based on the environ-
             ment variable "TZ", to be used by "ctime()", "local-
             time()", "mktime()", and "strftime()" functions.

     umask   This is identical to Perl's builtin "umask()" func-
             tion for setting (and querying) the file creation
             permission mask, see "umask" in perlfunc.

     uname   Get name of current operating system.

                     ($sysname, $nodename, $release, $version, $machine) = POSIX::uname();

             Note that the actual meanings of the various fields
             are not that well standardized, do not expect any
             great portability. The $sysname might be the name of
             the operating system, the $nodename might be the
             name of the host, the $release might be the (major)
             release number of the operating system, the $version
             might be the (minor) release number of the operating
             system, and the $machine might be a hardware iden-
             tifier. Maybe.

     ungetc  Use method "IO::Handle::ungetc()" instead.

     unlink  This is identical to Perl's builtin "unlink()"

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             function for removing files, see "unlink" in perl-
             func.

     utime   This is identical to Perl's builtin "utime()" func-
             tion for changing the time stamps of files and
             directories, see "utime" in perlfunc.

     vfprintf
             vfprintf() is C-specific, see "printf" in perlfunc
             instead.

     vprintf vprintf() is C-specific, see "printf" in perlfunc
             instead.

     vsprintf
             vsprintf() is C-specific, see "sprintf" in perlfunc
             instead.

     wait    This is identical to Perl's builtin "wait()" func-
             tion, see "wait" in perlfunc.

     waitpid Wait for a child process to change state.  This is
             identical to Perl's builtin "waitpid()" function,
             see "waitpid" in perlfunc.

                     $pid = POSIX::waitpid( -1, POSIX::WNOHANG );
                     print "status = ", ($? / 256), "\n";

     wcstombs
             This is identical to the C function "wcstombs()".
             Perl does not have any support for the wide and mul-
             tibyte characters of the C standards, so this might
             be a rather useless function.

     wctomb  This is identical to the C function "wctomb()". Perl
             does not have any support for the wide and multibyte
             characters of the C standards, so this might be a
             rather useless function.

     write   Write to a file.  This uses file descriptors such as
             those obtained by calling "POSIX::open".

                     $fd = POSIX::open( "foo", &POSIX::O_WRONLY );
                     $buf = "hello";
                     $bytes = POSIX::write( $b, $buf, 5 );

             Returns "undef" on failure.

             See also "syswrite" in perlfunc.

CLASSES


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     POSIX::SigAction

     new     Creates a new "POSIX::SigAction" object which
             corresponds to the C "struct sigaction".  This
             object will be destroyed automatically when it is no
             longer needed.  The first parameter is the fully-
             qualified name of a sub which is a signal-handler.
             The second parameter is a "POSIX::SigSet" object, it
             defaults to the empty set.  The third parameter con-
             tains the "sa_flags", it defaults to 0.

                     $sigset = POSIX::SigSet->new(SIGINT, SIGQUIT);
                     $sigaction = POSIX::SigAction->new( \&main::handler, $sigset, &POSIX::SA_NOCLDSTOP );

             This "POSIX::SigAction" object is intended for use
             with the "POSIX::sigaction()" function.

     handler
     mask
     flags   accessor functions to get/set the values of a SigAc-
             tion object.

                     $sigset = $sigaction->mask;
                     $sigaction->flags(&POSIX::SA_RESTART);

     safe    accessor function for the "safe signals" flag of a
             SigAction object; see perlipc for general informa-
             tion on safe (a.k.a. "deferred") signals.  If you
             wish to handle a signal safely, use this accessor to
             set the "safe" flag in the "POSIX::SigAction"
             object:

                     $sigaction->safe(1);

             You may also examine the "safe" flag on the output
             action object which is filled in when given as the
             third parameter to "POSIX::sigaction()":

                     sigaction(SIGINT, $new_action, $old_action);
                     if ($old_action->safe) {
                         # previous SIGINT handler used safe signals
                     }

     POSIX::SigSet

     new     Create a new SigSet object.  This object will be
             destroyed automatically when it is no longer needed.
             Arguments may be supplied to initialize the set.

             Create an empty set.

                     $sigset = POSIX::SigSet->new;

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             Create a set with SIGUSR1.

                     $sigset = POSIX::SigSet->new( &POSIX::SIGUSR1 );

     addset  Add a signal to a SigSet object.

                     $sigset->addset( &POSIX::SIGUSR2 );

             Returns "undef" on failure.

     delset  Remove a signal from the SigSet object.

                     $sigset->delset( &POSIX::SIGUSR2 );

             Returns "undef" on failure.

     emptyset
             Initialize the SigSet object to be empty.

                     $sigset->emptyset();

             Returns "undef" on failure.

     fillset Initialize the SigSet object to include all signals.

                     $sigset->fillset();

             Returns "undef" on failure.

     ismember
             Tests the SigSet object to see if it contains a
             specific signal.

                     if( $sigset->ismember( &POSIX::SIGUSR1 ) ){
                             print "contains SIGUSR1\n";
                     }

     POSIX::Termios

     new     Create a new Termios object.  This object will be
             destroyed automatically when it is no longer needed.
             A Termios object corresponds to the termios C
             struct.  new() mallocs a new one, getattr() fills it
             from a file descriptor, and setattr() sets a file
             descriptor's parameters to match Termios' contents.

                     $termios = POSIX::Termios->new;

     getattr Get terminal control attributes.

             Obtain the attributes for stdin.

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                     $termios->getattr()

             Obtain the attributes for stdout.

                     $termios->getattr( 1 )

             Returns "undef" on failure.

     getcc   Retrieve a value from the c_cc field of a termios
             object.  The c_cc field is an array so an index must
             be specified.

                     $c_cc[1] = $termios->getcc(1);

     getcflag
             Retrieve the c_cflag field of a termios object.

                     $c_cflag = $termios->getcflag;

     getiflag
             Retrieve the c_iflag field of a termios object.

                     $c_iflag = $termios->getiflag;

     getispeed
             Retrieve the input baud rate.

                     $ispeed = $termios->getispeed;

     getlflag
             Retrieve the c_lflag field of a termios object.

                     $c_lflag = $termios->getlflag;

     getoflag
             Retrieve the c_oflag field of a termios object.

                     $c_oflag = $termios->getoflag;

     getospeed
             Retrieve the output baud rate.

                     $ospeed = $termios->getospeed;

     setattr Set terminal control attributes.

             Set attributes immediately for stdout.

                     $termios->setattr( 1, &POSIX::TCSANOW );

             Returns "undef" on failure.

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     setcc   Set a value in the c_cc field of a termios object.
             The c_cc field is an array so an index must be
             specified.

                     $termios->setcc( &POSIX::VEOF, 1 );

     setcflag
             Set the c_cflag field of a termios object.

                     $termios->setcflag( $c_cflag | &POSIX::CLOCAL );

     setiflag
             Set the c_iflag field of a termios object.

                     $termios->setiflag( $c_iflag | &POSIX::BRKINT );

     setispeed
             Set the input baud rate.

                     $termios->setispeed( &POSIX::B9600 );

             Returns "undef" on failure.

     setlflag
             Set the c_lflag field of a termios object.

                     $termios->setlflag( $c_lflag | &POSIX::ECHO );

     setoflag
             Set the c_oflag field of a termios object.

                     $termios->setoflag( $c_oflag | &POSIX::OPOST );

     setospeed
             Set the output baud rate.

                     $termios->setospeed( &POSIX::B9600 );

             Returns "undef" on failure.

     Baud rate values
             B38400 B75 B200 B134 B300 B1800 B150 B0 B19200 B1200
             B9600 B600 B4800 B50 B2400 B110

     Terminal interface values
             TCSADRAIN TCSANOW TCOON TCIOFLUSH TCOFLUSH TCION
             TCIFLUSH TCSAFLUSH TCIOFF TCOOFF

     c_cc field values
             VEOF VEOL VERASE VINTR VKILL VQUIT VSUSP VSTART
             VSTOP VMIN VTIME NCCS

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     c_cflag field values
             CLOCAL CREAD CSIZE CS5 CS6 CS7 CS8 CSTOPB HUPCL
             PARENB PARODD

     c_iflag field values
             BRKINT ICRNL IGNBRK IGNCR IGNPAR INLCR INPCK ISTRIP
             IXOFF IXON PARMRK

     c_lflag field values
             ECHO ECHOE ECHOK ECHONL ICANON IEXTEN ISIG NOFLSH
             TOSTOP

     c_oflag field values
             OPOST

PATHNAME CONSTANTS

     Constants
             _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

POSIX CONSTANTS

     Constants
             _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

SYSTEM CONFIGURATION

     Constants
             _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

ERRNO

     Constants
             E2BIG EACCES EADDRINUSE EADDRNOTAVAIL EAFNOSUPPORT
             EAGAIN EALREADY EBADF EBUSY ECHILD ECONNABORTED
             ECONNREFUSED ECONNRESET EDEADLK EDESTADDRREQ EDOM
             EDQUOT EEXIST EFAULT EFBIG EHOSTDOWN EHOSTUNREACH
             EINPROGRESS EINTR EINVAL EIO EISCONN EISDIR ELOOP
             EMFILE EMLINK EMSGSIZE ENAMETOOLONG ENETDOWN
             ENETRESET ENETUNREACH ENFILE ENOBUFS ENODEV ENOENT
             ENOEXEC ENOLCK ENOMEM ENOPROTOOPT ENOSPC ENOSYS
             ENOTBLK ENOTCONN ENOTDIR ENOTEMPTY ENOTSOCK ENOTTY
             ENXIO EOPNOTSUPP EPERM EPFNOSUPPORT EPIPE EPROCLIM
             EPROTONOSUPPORT EPROTOTYPE ERANGE EREMOTE ERESTART
             EROFS ESHUTDOWN ESOCKTNOSUPPORT ESPIPE ESRCH ESTALE

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             ETIMEDOUT ETOOMANYREFS ETXTBSY EUSERS EWOULDBLOCK
             EXDEV

FCNTL

     Constants
             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

FLOAT

     Constants
             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

LIMITS

     Constants
             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

LOCALE

     Constants
             LC_ALL LC_COLLATE LC_CTYPE LC_MONETARY LC_NUMERIC
             LC_TIME

MATH

     Constants
             HUGE_VAL

SIGNAL

     Constants
             SA_NOCLDSTOP SA_NOCLDWAIT SA_NODEFER SA_ONSTACK
             SA_RESETHAND SA_RESTART SA_SIGINFO SIGABRT SIGALRM
             SIGCHLD SIGCONT SIGFPE SIGHUP SIGILL SIGINT SIGKILL
             SIGPIPE SIGQUIT SIGSEGV SIGSTOP SIGTERM SIGTSTP
             SIGTTIN SIGTTOU SIGUSR1 SIGUSR2 SIG_BLOCK SIG_DFL
             SIG_ERR SIG_IGN SIG_SETMASK SIG_UNBLOCK

STAT

     Constants
             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

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     Macros  S_ISBLK S_ISCHR S_ISDIR S_ISFIFO S_ISREG

STDLIB

     Constants
             EXIT_FAILURE EXIT_SUCCESS MB_CUR_MAX RAND_MAX

STDIO

     Constants
             BUFSIZ EOF FILENAME_MAX L_ctermid L_cuserid
             L_tmpname TMP_MAX

TIME

     Constants
             CLK_TCK CLOCKS_PER_SEC

UNISTD

     Constants
             R_OK SEEK_CUR SEEK_END SEEK_SET STDIN_FILENO
             STDOUT_FILENO STDERR_FILENO W_OK X_OK

WAIT

     Constants
             WNOHANG WUNTRACED

             WNOHANG         Do not suspend the calling process
                             until a child process changes state
                             but instead return immediately.

             WUNTRACED       Catch stopped child processes.

     Macros  WIFEXITED WEXITSTATUS WIFSIGNALED WTERMSIG WIFS-
             TOPPED WSTOPSIG

             WIFEXITED       WIFEXITED($?) returns true if the
                             child process exited normally
                             ("exit()" or by falling off the end
                             of "main()")

             WEXITSTATUS     WEXITSTATUS($?) returns the normal
                             exit status of the child process
                             (only meaningful if WIFEXITED($?) is
                             true)

             WIFSIGNALED     WIFSIGNALED($?) returns true if the
                             child process terminated because of
                             a signal

             WTERMSIG        WTERMSIG($?) returns the signal the
                             child process terminated for (only
                             meaningful if WIFSIGNALED($?) is
                             true)

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             WIFSTOPPED      WIFSTOPPED($?) returns true if the
                             child process is currently stopped
                             (can happen only if you specified
                             the WUNTRACED flag to waitpid())

             WSTOPSIG        WSTOPSIG($?) returns the signal the
                             child process was stopped for (only
                             meaningful if WIFSTOPPED($?) is
                             true)

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