


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
       identifiers 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
       function, 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
       available 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
       suggest 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 successfully 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()"
               function, 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
               argument.  See also Math::Trig.

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



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               function, 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.  $wday and
               $yday default to zero (and are usually ignored
               anyway), and $isdst defaults to -1.

       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
               argument.  See also Math::Trig.

       atan2   This is identical to Perl's builtin "atan2()"
               function, 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.

       bsearch bsearch() not supplied.  For doing binary search



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               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()"
               function, allowing one to change the working
               (default) directory, see "chdir" in perlfunc.

       chmod   This is identical to Perl's builtin "chmod()"
               function, allowing one to change file and
               directory permissions, see "chmod" in perlfunc.

       chown   This is identical to Perl's builtin "chown()"
               function, allowing one to change file and
               directory owners 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()"
               function, 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
               returning the hyperbolic cosine of its numeric
               argument.  See also Math::Trig.



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       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
               terminal.

                       $path = POSIX::ctermid();

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

       cuserid Get the login name of the owner of the current
               process.

                       $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.

       errno   Returns the value of errno.

                       $errno = POSIX::errno();




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               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()"
               function for exiting the program, see "exit" in
               perlfunc.

       exp     This is identical to Perl's builtin "exp()"
               function for returning the exponent (e-based) of
               the numerical 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()"
               function, 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 "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



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               "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
               magnitude of $y.

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

       fork    This is identical to Perl's builtin "fork()"
               function 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
               instead.

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

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



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       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
               expressions 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
               builtin "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()"
               function, 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
               variable.  The same information is available
               through the %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
               perlvar.



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

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



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       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()"
               function for converting seconds since the epoch to
               a date in Greenwich Mean Time, see "gmtime" in
               perlfunc.

       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 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.




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       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 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:]]/"



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               construct instead, or simply "/[0-9a-f]/i".

       kill    This is identical to Perl's builtin "kill()"
               function for sending signals to processes (often
               to terminate 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()"
               function 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.

                       $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";





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       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()"
               function, 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".

                       $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
               multibyte 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.



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

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

       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()"
               function for creating directories, see "mkdir" in
               perlfunc.

       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,
               though for "mkfifo" you must specify the $mode.

       mktime  Convert date/time info to a calendar time.

               Synopsis:

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




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       nice    This is similar to the C function "nice()", for
               changing the scheduling preference of the current
               process.  Positive arguments mean more polite
               process, 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 );

               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 );



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               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.

                       $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



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               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
               "readdir" in perlfunc.

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

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

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

       rewind  Seeks to the beginning of the file.

       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()"
               function for removing (empty) directories, see
               "rmdir" in perlfunc.

       scanf   scanf() is C-specific, use <> and regular
               expressions 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 $)
               variable, see "$EGID" 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



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               following 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
               availability of locales depends on your operating
               system. 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
               process.

       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 (the oldaction can also be
               just a hash reference).  Consult your system's



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               "sigaction" manpage for details, see also
               "POSIX::SigRt".

               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.

               If you use the SA_SIGINFO flag, the signal handler
               will in addition to the first argument, the signal
               name, also receive a second argument, a hash
               reference, inside which are the following keys
               with the following semantics, as defined by
               POSIX/SUSv3:

                   signo       the signal number
                   errno       the error number
                   code        if this is zero or less, the signal was sent by
                               a user process and the uid and pid make sense,
                               otherwise the signal was sent by the kernel

               The following are also defined by POSIX/SUSv3, but
               unfortunately not very widely implemented:

                   pid         the process id generating the signal
                   uid         the uid of the process id generating the signal
                   status      exit value or signal for SIGCHLD
                   band        band event for SIGPOLL

               A third argument is also passed to the handler,
               which contains a copy of the raw binary contents
               of the siginfo structure: if a system has some
               non-POSIX fields, this third argument is where to
               unpack() them from.

               Note that not all siginfo values make sense
               simultaneously (some are valid only for certain
               signals, for example), and not all values make
               sense from Perl perspective, you should to consult
               your system's "sigaction" and possibly also
               "siginfo" documentation.

       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"
               argument.  Consult your system's "sigpending"



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               manpage for details.

               Synopsis:

                       sigpending(sigset)

               Returns "undef" on failure.

       sigprocmask
               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
               signal 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
               argument.  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
               significant difference, however: "POSIX::sleep()"
               returns the number of unslept seconds, while the
               "CORE::sleep()" returns the number of slept
               seconds.




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

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

       srand   Give a seed the pseudorandom number generator, see
               "srand" in perlfunc.

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

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

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

       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



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               ("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
               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
               perlop.

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

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

       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.



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       strstr  This is identical to Perl's builtin "index()"
               function, 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 systems set $! ($ERRNO) to indicate a
               translation error, so clear $! before calling
               strtod.  However, non-POSIX systems may not check
               for overflow, and therefore will never set $!.

               strtod should respect any POSIX setlocale()
               settings.

               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()
               settings.

               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



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               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 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
               transparently, 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()"
               function, see "system" in perlfunc.

       tan     This is identical to the C function "tan()",
               returning 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.




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

               Returns "undef" on failure.

       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
               terminal.

       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
               foreground process group of the controlling
               terminal.

               Returns "undef" on failure.

       time    This is identical to Perl's builtin "time()"
               function 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.




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       tmpnam  Returns a name for a temporary file.

                       $tmpfile = POSIX::tmpnam();

               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
               environment variable "TZ", to be used by
               "ctime()", "localtime()", "mktime()", and
               "strftime()" functions.

       umask   This is identical to Perl's builtin "umask()"
               function 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 identifier.  Maybe.




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

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

       utime   This is identical to Perl's builtin "utime()"
               function 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()"
               function, 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
               multibyte 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( $fd, $buf, 5 );

               Returns "undef" on failure.

               See also "syswrite" in perlfunc.





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CLASSES
   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
               handler, a sub reference.  The second parameter is
               a "POSIX::SigSet" object, it defaults to the empty
               set.  The third parameter contains the "sa_flags",
               it defaults to 0.

                       $sigset = POSIX::SigSet->new(SIGINT, SIGQUIT);
                       $sigaction = POSIX::SigAction->new( \&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
               SigAction 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
               information 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::SigRt
       %SIGRT  A hash of the POSIX realtime signal handlers.  It
               is an extension of the standard %SIG, the
               $POSIX::SIGRT{SIGRTMIN} is roughly equivalent to
               $SIG{SIGRTMIN}, but the right POSIX moves (see
               below) are made with the POSIX::SigSet and
               POSIX::sigaction instead of accessing the %SIG.

               You can set the %POSIX::SIGRT elements to set the
               POSIX realtime signal handlers, use "delete" and
               "exists" on the elements, and use "scalar" on the



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               %POSIX::SIGRT to find out how many POSIX realtime
               signals there are available (SIGRTMAX - SIGRTMIN +
               1, the SIGRTMAX is a valid POSIX realtime signal).

               Setting the %SIGRT elements is equivalent to
               calling this:

                 sub new {
                   my ($rtsig, $handler, $flags) = @_;
                   my $sigset = POSIX::SigSet($rtsig);
                   my $sigact = POSIX::SigAction->new($handler, $sigset, $flags);
                   sigaction($rtsig, $sigact);
                 }

               The flags default to zero, if you want something
               different you can either use "local" on
               $POSIX::SigRt::SIGACTION_FLAGS, or you can derive
               from POSIX::SigRt and define your own "new()" (the
               tied hash STORE method of the %SIGRT calls
               "new($rtsig, $handler, $SIGACTION_FLAGS)", where
               the $rtsig ranges from zero to SIGRTMAX - SIGRTMIN
               + 1).

               Just as with any signal, you can use
               sigaction($rtsig, undef, $oa) to retrieve the
               installed signal handler (or, rather, the signal
               action).

               NOTE: whether POSIX realtime signals really work
               in your system, or whether Perl has been compiled
               so that it works with them, is outside of this
               discussion.

       SIGRTMIN
               Return the minimum POSIX realtime signal number
               available, or "undef" if no POSIX realtime signals
               are available.

       SIGRTMAX
               Return the maximum POSIX realtime signal number
               available, or "undef" if no POSIX realtime signals
               are available.

   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;

               Create a set with SIGUSR1.



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                       $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.

                       $termios->getattr( 0 ) # Recommended for clarity.
                       $termios->getattr()




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               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.

       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.




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                       $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

       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



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               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 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



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               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

       Macros  S_ISBLK S_ISCHR S_ISDIR S_ISFIFO S_ISREG

STDLIB
       Constants
               EXIT_FAILURE EXIT_SUCCESS MB_CUR_MAX RAND_MAX





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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
               WIFSTOPPED 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)

               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



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                               (only meaningful if WIFSTOPPED($?)
                               is true)























































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