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POSIX(3) - POSIX - Perl interface to IEEE Std 1003.1 - man 3 POSIX

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



NAME
       POSIX - Perl interface to IEEE Std 1003.1

SYNOPSIS
           use POSIX;
           use POSIX qw(setsid(2,8));
           use POSIX qw(:errno_h :fcntl_h);

           printf(1,3,1 builtins) "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(2,5) 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 func-
       tions with the same name as a built-in Perl function, such as "abs",
       "alarm(1,2)", "rmdir(1,2)", "write(1,2)", etc.., which will be exported only if(3,n) you
       ask for them explicitly.  This is an unfortunate backwards compatibil-
       ity 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(1,8) 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 specifica-
       tion.  The second section describes some classes for signal(2,7) objects,
       TTY objects, and other miscellaneous objects.  The remaining sections
       list various constants and macros in(1,8) an organization which roughly fol-
       lows 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(1,8) 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 example, trying to access(2,5) 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(1,8)
       fact are not so: they will not pass the PCTS (POSIX Compliance Test
       Suites).  For example, one vendor may not define EDEADLK, or the seman-
       tics of the errno values set(7,n,1 builtins) by open(2,3,n)(2) might not be quite right.  Perl
       does not attempt to verify(1,8) POSIX compliance.  That means you can cur-
       rently successfully say "use POSIX",  and then later in(1,8) 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(1,8) Linux this is not a good
               way to exit(3,n,1 builtins) a thread because in(1,8) Linux processes and threads are
               kind of the same thing (Note: while this is the situation in(1,8)
               early 2003 there are projects under way to have threads with
               more POSIXly semantics in(1,8) Linux).  If you want not to return
               from a thread, detach the thread.

       abort(3,7)   This is identical to the C function "abort(3,7)()".  It terminates
               the process with a "SIGABRT" signal(2,7) unless caught by a signal(2,7)
               handler or if(3,n) 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(2,5)  Determines the accessibility of a file.

                       if(3,n)( POSIX::access( "/", &POSIX::R_OK ) ){
                               print "have read(2,n,1 builtins) permission\n";
                       }

               Returns "undef" on failure.  Note: do not use "access(2,5)()" for
               security purposes.  Between the "access(2,5)()" call and the opera-
               tion 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(1,2)   This is identical to Perl's builtin "alarm(1,2)()" function, either
               for arming or disarming the "SIGARLM" timer.

       asctime This is identical to the C function "asctime()".  It returns a
               string(3,n) 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(1,8) 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, return-
               ing 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 trans-
               parently.  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 trans-
               parently.  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(1,8) perlfunc.

       atol    atol() is C-specific.  Perl converts strings to numbers trans-
               parently.  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(1,8) perlfunc.

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

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

       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, allow-
               ing one to change the working (default) directory, see "chdir"
               in(1,8) perlfunc.

       chmod(1,2)   This is identical to Perl's builtin "chmod(1,2)()" function, allow-
               ing one to change file(1,n) and directory permissions, see "chmod(1,2)"
               in(1,8) perlfunc.

       chown(1,2)   This is identical to Perl's builtin "chown(1,2)()" function, allow-
               ing one to change file(1,n) and directory owners and groups, see
               "chown(1,2)" in(1,8) perlfunc.

       clearerr
               Use the method "IO::Handle::clearerr()" instead, to reset(1,7,1 tput) the
               error(8,n) state (if(3,n) any) and EOF state (if(3,n) any) of the given
               stream.

       clock(3,n)   This is identical to the C function "clock(3,n)()", returning the
               amount of spent processor time(1,2,n) in(1,8) microseconds.

       close(2,7,n)   Close the file.  This uses file(1,n) 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(2,7,n)" in(1,8) perlfunc.

       closedir
               This is identical to Perl's builtin "closedir()" function for
               closing a directory handle, see "closedir" in(1,8) perlfunc.

       cos     This is identical to Perl's builtin "cos()" function, for
               returning the cosine of its numerical argument, see "cos" in(1,8)
               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.

       creat   Create a new file.  This returns a file(1,n) descriptor like the
               ones returned by "POSIX::open".  Use "POSIX::close" to close(2,7,n)
               the file.

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

               See also "sysopen" in(1,8) 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(1,3,5) name of the owner of the current process.

                       $name = POSIX::cuserid();

       difftime
               This is identical to the C function "difftime()", for returning
               the time(1,2,n) difference (in(1,8) seconds) between two times (as returned
               by "time(1,2,n)()"), see "time(1,2,n)".

       div     div() is C-specific, use "int" in(1,8) perlfunc on the usual "/"
               division and the modulus "%".

       dup     This is similar to the C function "dup()", for duplicating a
               file(1,n) descriptor.

               This uses file(1,n) 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(1,n) descriptor to an another known file(1,n) descriptor.

               This uses file(1,n) descriptors such as those obtained by calling
               "POSIX::open".

               Returns "undef" on failure.

       errno   Returns the value of errno.

                       $errno = POSIX::errno();

               This identical to the numerical values of the $!, see "$ERRNO"
               in(1,8) perlvar.

       execl   execl() is C-specific, see "exec(3,n,1 builtins)" in(1,8) perlfunc.

       execle  execle() is C-specific, see "exec(3,n,1 builtins)" in(1,8) perlfunc.

       execlp  execlp() is C-specific, see "exec(3,n,1 builtins)" in(1,8) perlfunc.

       execv   execv() is C-specific, see "exec(3,n,1 builtins)" in(1,8) perlfunc.

       execve  execve() is C-specific, see "exec(3,n,1 builtins)" in(1,8) perlfunc.

       execvp  execvp() is C-specific, see "exec(3,n,1 builtins)" in(1,8) perlfunc.

       exit(3,n,1 builtins)    This is identical to Perl's builtin "exit(3,n,1 builtins)()" function for exit-
               ing the program, see "exit(3,n,1 builtins)" in(1,8) perlfunc.

       exp     This is identical to Perl's builtin "exp()" function for
               returning the exponent (e-based) of the numerical argument, see
               "exp" in(1,8) perlfunc.

       fabs    This is identical to Perl's builtin "abs()" function for
               returning the absolute value of the numerical argument, see
               "abs" in(1,8) perlfunc.

       fclose  Use method "IO::Handle::close()" instead, or see "close(2,7,n)" in(1,8)
               perlfunc.

       fcntl   This is identical to Perl's builtin "fcntl()" function, see
               "fcntl" in(1,8) perlfunc.

       fdopen  Use method "IO::Handle::new_from_fd()" instead, or see "open(2,3,n)"
               in(1,8) perlfunc.

       feof    Use method "IO::Handle::eof()" instead, or see "eof" in(1,8) perl-
               func.

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

       fflush  Use method "IO::Handle::flush()" instead.  See also "$OUT-
               PUT_AUTOFLUSH" in(1,8) perlvar.

       fgetc   Use method "IO::Handle::getc()" instead, or see "read(2,n,1 builtins)" in(1,8) perl-
               func.

       fgetpos Use method "IO::Seekable::getpos()" instead, or see "seek" in(1,8)
               L.

       fgets   Use method "IO::Handle::gets()" instead.  Similar to <>, also
               known as "readline" in(1,8) perlfunc.

       fileno  Use method "IO::Handle::fileno()" instead, or see "fileno" in(1,8)
               perlfunc.

       floor   This is identical to the C function "floor()", returning the
               largest integer value less(1,3) than or equal to the numerical argu-
               ment.

       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(1,3) than the magnitude of $y.

       fopen   Use method "IO::File::open()" instead, or see "open(2,3,n)" in(1,8) perl-
               func.

       fork    This is identical to Perl's builtin "fork()" function for
               duplicating the current process, see "fork" in(1,8) perlfunc and
               perlfork if(3,n) you are in(1,8) Windows.

       fpathconf
               Retrieves the value of a configurable limit on a file(1,n) or direc-
               tory.  This uses file(1,n) 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(1,3,1 builtins)" in(1,8) perlfunc instead.

       fputc   fputc() is C-specific, see "print" in(1,8) perlfunc instead.

       fputs   fputs() is C-specific, see "print" in(1,8) perlfunc instead.

       fread   fread() is C-specific, see "read(2,n,1 builtins)" in(1,8) perlfunc instead.

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

       freopen freopen() is C-specific, see "open(2,3,n)" in(1,8) 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 expressions instead.

       fseek   Use method "IO::Seekable::seek()" instead, or see "seek" in(1,8)
               perlfunc.

       fsetpos Use method "IO::Seekable::setpos()" instead, or seek "seek" in(1,8)
               perlfunc.

       fstat   Get file(1,n) status.  This uses file(1,n) descriptors such as those
               obtained by calling "POSIX::open".  The data returned is iden-
               tical to the data from Perl's builtin "stat(1,2)" 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(1,8)
               perlfunc.

       fwrite  fwrite() is C-specific, see "print" in(1,8) perlfunc instead.

       getc    This is identical to Perl's builtin "getc()" function, see
               "getc" in(1,8) perlfunc.

       getchar Returns one character from STDIN.  Identical to Perl's
               "getc()", see "getc" in(1,8) 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(1,8) perlvar.

       getenv  Returns the value of the specified enironment 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(1,8) perlvar.

       getgid  Returns the user's real group identifier.  Similar to Perl's
               builtin variable $), see "$GID" in(1,8) perlvar.

       getgrgid
               This is identical to Perl's builtin "getgrgid()" function for
               returning group entries by group identifiers, see "getgrgid" in(1,8)
               perlfunc.

       getgrnam
               This is identical to Perl's builtin "getgrnam()" function for
               returning group entries by group names, see "getgrnam" in(1,8) perl-
               func.

       getgroups
               Returns the ids of the user's supplementary groups.  Similar to
               Perl's builtin variable $), see "$GID" in(1,8) perlvar.

       getlogin
               This is identical to Perl's builtin "getlogin()" function for
               returning the user name associated with the current session,
               see "getlogin" in(1,8) perlfunc.

       getpgrp This is identical to Perl's builtin "getpgrp()" function for
               returning the prcess group identifier of the current process,
               see "getpgrp" in(1,8) perlfunc.

       getpid  Returns the process identifier.  Identical to Perl's builtin
               variable $$, see "$PID" in(1,8) 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(1,8) perlfunc.

       getpwnam
               This is identical to Perl's builtin "getpwnam()" function for
               returning user entries by user names, see "getpwnam" in(1,8) perl-
               func.

       getpwuid
               This is identical to Perl's builtin "getpwuid()" function for
               returning user entries by user identifiers, see "getpwuid" in(1,8)
               perlfunc.

       gets(3,n)    Returns one line from "STDIN", similar to <>, also known as the
               "readline()" function, see "readline" in(1,8) perlfunc.

               NOTE: if(3,n) you have C programs that still use "gets(3,n)()", be very
               afraid.  The "gets(3,n)()" 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(1,8) perlvar.

       gmtime  This is identical to Perl's builtin "gmtime()" function for
               converting seconds since the epoch to a date in(1,8) Greenwich Mean
               Time, see "gmtime" in(1,8) 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(3,5,7)
               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:]]/" con-
               struct 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(3,5,7)
               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:]]/" con-
               struct instead.

       isatty  Returns a boolean indicating whether the specified filehandle
               is connected to a tty.  Similar to the "-t" operator, see "-X"
               in(1,8) 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(3,5,7)
               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:]]/" con-
               struct 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(3,5,7)
               settings may affect what characters are considered "isdigit"
               (unlikely, but still possible). Does not work on Unicode char-
               acters 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(3,5,7)
               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:]]/" con-
               struct 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(3,5,7)
               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:]]/" con-
               struct 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(3,5,7)
               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:]]/" con-
               struct 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(3,5,7)
               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:]]/" con-
               struct 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(3,5,7)
               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:]]/" con-
               struct instead, or the "/\s/" construct.  (Note that "/\s/" and
               "/[[:space:]]/" are slightly different in(1,8) 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(3,5,7)
               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:]]/" con-
               struct 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(3,5,7)
               settings may affect what characters are considered "isxdigit"
               (unlikely, but still possible).  Does not work on Unicode char-
               acters code point 256 or higher.  Consider using regular
               expressions and the "/[[:xdigit:]]/" construct instead, or sim-
               ply "/[0-9a-f]/i".

       kill(1,2,1 builtins)    This is identical to Perl's builtin "kill(1,2,1 builtins)()" function for send-
               ing signals to processes (often to terminate them), see "kill(1,2,1 builtins)"
               in(1,8) perlfunc.

       labs    (For returning absolute values of long integers.)  labs() is
               C-specific, see "abs" in(1,8) 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-spe-
               cific, use "/" and "int()" instead.

       link(1,2)    This is identical to Perl's builtin "link(1,2)()" function for cre-
               ating hard links into files, see "link(1,2)" in(1,8) perlfunc.

       localeconv
               Get numeric formatting information.  Returns a reference to a
               hash containing the current locale(3,5,7) formatting values.

               Here is how to query the database for the de (Deutsch or Ger-
               man(1,5,7)) 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";

       localtime
               This is identical to Perl's builtin "localtime()" function for
               converting seconds since the epoch to a date see "localtime" in(1,8)
               perlfunc.

       log     This is identical to Perl's builtin "log()" function, returning
               the natural (e-based) logarithm of the numerical argument, see
               "log" in(1,8) 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(1,8) perlfunc instead.

       lseek   Move the file(1,n)'s read(2,n,1 builtins)/write(1,2) position.  This uses file(1,n) descrip-
               tors 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 transpar-
               ently.

       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.

       memchr  memchr() is C-specific, see "index" in(1,8) perlfunc instead.

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

       memcpy  memcpy() is C-specific, use "=", see perlop, or see "substr" in(1,8)
               perlfunc.

       memmove memmove() is C-specific, use "=", see perlop, or see "substr"
               in(1,8) perlfunc.

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

       mkdir(1,2)   This is identical to Perl's builtin "mkdir(1,2)()" function for cre-
               ating directories, see "mkdir(1,2)" in(1,8) perlfunc.

       mkfifo(1,3)  This is similar to the C function "mkfifo(1,3)()" for creating FIFO
               special files.

                       if(3,n) (mkfifo(1,3)($path, $mode)) { ....

               Returns "undef" on failure.  The $mode is similar to the mode
               of "mkdir(1,2)()", see "mkdir(1,2)" in(1,8) perlfunc.

       mktime  Convert date/time(1,2,n) info(1,5,n) to a calendar time.

               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(1,8) 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(1,2,n) 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(1,2)    This is similar to the C function "nice(1,2)()", for changing the
               scheduling preference of the current process.  Positive argu-
               ments 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(3,n,n pack-old)" in(1,8)
               perlfunc instead.

       open(2,3,n)    Open a file(1,n) for reading for writing.  This returns file(1,n)
               descriptors, not Perl filehandles.  Use "POSIX::close" to close(2,7,n)
               the file.

               Open a file(1,n) read-only with mode 0666.

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

               Open a file(1,n) for read(2,n,1 builtins) and write.

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

               Open a file(1,n) for write(1,2), with truncation.

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

               Create a new file(1,n) with mode 0640.  Set up the file(1,n) for writing.

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

               Returns "undef" on failure.

               See also "sysopen" in(1,8) 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(1,n) or direc-
               tory.

               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(2,7) is received.

               Returns "undef" on failure.

       perror(1,3)  This is identical to the C function "perror(1,3)()", which outputs
               to the standard error(8,n) stream the specified message followed by
               ": " and the current error(8,n) string.  Use the "warn()" function
               and the $!  variable instead, see "warn" in(1,8) perlfunc and
               "$ERRNO" in(1,8) perlvar.

       pipe(2,8)    Create an interprocess channel.  This returns file(1,n) descriptors
               like those returned by "POSIX::open".

                       ($fd0, $fd1) = POSIX::pipe();
                       POSIX::write( $fd0, "hello", 5 );
                       POSIX::read( $fd1, $buf, 5 );

               See also "pipe(2,8)" in(1,8) perlfunc.

       pow     Computes $x raised to the power $exponent.

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

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

       printf(1,3,1 builtins)  Formats and prints the specified arguments to STDOUT.  See also
               "printf(1,3,1 builtins)" in(1,8) perlfunc.

       putc    putc() is C-specific, see "print" in(1,8) perlfunc instead.

       putchar putchar() is C-specific, see "print" in(1,8) perlfunc instead.

       puts(3,n)    puts(3,n)() is C-specific, see "print" in(1,8) perlfunc instead.

       qsort   qsort() is C-specific, see "sort(1,3)" in(1,8) perlfunc instead.

       raise(3,n)   Sends the specified signal(2,7) to the current process.  See also
               "kill(1,2,1 builtins)" in(1,8) perlfunc and the $$ in(1,8) "$PID" in(1,8) perlvar.

       rand(1,3)    "rand(1,3)()" is non-portable, see "rand(1,3)" in(1,8) perlfunc instead.

       read(2,n,1 builtins)    Read from a file.  This uses file(1,n) descriptors such as those
               obtained by calling "POSIX::open".  If the buffer $buf is not
               large enough for the read(2,n,1 builtins) 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(1,8) perlfunc.

       readdir(2,3) This is identical to Perl's builtin "readdir(2,3)()" function for
               reading directory entries, see "readdir(2,3)" in(1,8) perlfunc.

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

       remove  This is identical to Perl's builtin "unlink(1,2)()" function for
               removing files, see "unlink(1,2)" in(1,8) perlfunc.

       rename(1,2,n)  This is identical to Perl's builtin "rename(1,2,n)()" function for
               renaming files, see "rename(1,2,n)" in(1,8) 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(1,8) perlfunc.

       rmdir(1,2)   This is identical to Perl's builtin "rmdir(1,2)()" function for
               removing (empty) directories, see "rmdir(1,2)" in(1,8) perlfunc.

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

       setgid  Sets the real group identifier and the effective group identi-
               fier for this process.  Similar to assigning a value to the
               Perl's builtin $) variable, see "$GID" in(1,8) 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(1,8)
               perlfunc.

       setlocale
               Modifies and queries program's locale.  The following examples
               assume

                       use POSIX qw(setlocale LC_ALL LC_CTYPE);

               has been issued.

               The following will set(7,n,1 builtins) the traditional UNIX system locale(3,5,7)
               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(7,n,1 builtins) the LC_CTYPE behaviour according to the
               locale(3,5,7) environment variables (the second argument "").  Please
               see your systems setlocale(3) documentation for the locale(3,5,7)
               environment variables' meaning or consult perllocale.

                       $loc = setlocale( LC_CTYPE, "" );

               The following will set(7,n,1 builtins) 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(1,8) 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(2,8)  This is identical to the C function "setsid(2,8)()" 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(1,8) perlvar, except that the
               latter will change only the real user identifier.

       sigaction
               Detailed signal(2,7) management.  This uses "POSIX::SigAction"
               objects for the "action" and "oldaction" arguments.  Consult
               your system's "sigaction" manpage for details.

               Synopsis:

                       sigaction(signal(2,7), action, oldaction = 0)

               Returns "undef" on failure.  The "signal(2,7)" must be a number
               (like SIGHUP), not a string(3,n) (like "SIGHUP"), though Perl does
               try hard to understand you.

       siglongjmp
               siglongjmp() is C-specific: use "die" in(1,8) perlfunc instead.

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

               Synopsis:

                       sigpending(sigset)

               Returns "undef" on failure.

       sigprocmask
               Change and/or examine calling process's signal(2,7) mask.  This uses
               "POSIX::SigSet" objects for the "sigset" and "oldsigset" argu-
               ments.  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(1,8) perlfunc.

       sigsuspend
               Install a signal(2,7) mask and suspend process until signal(2,7) arrives.
               This uses "POSIX::SigSet" objects for the "signal_mask" argu-
               ment.  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(1,8)
               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(1,3)   This is functionally identical to Perl's builtin "sleep(1,3)()"
               function for suspending the execution of the current for
               process for certain number of seconds, see "sleep(1,3)" in(1,8) 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.

       sprintf This is similar to Perl's builtin "sprintf()" function for
               returning a string(3,n) that has the arguments formatted as
               requested, see "sprintf" in(1,8) perlfunc.

       sqrt    This is identical to Perl's builtin "sqrt()" function.  for
               returning the square root of the numerical argument, see "sqrt"
               in(1,8) perlfunc.

       srand   Give a seed the pseudorandom number generator, see "srand" in(1,8)
               perlfunc.

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

       stat(1,2)    This is identical to Perl's builtin "stat(1,2)()" function for
               retutning information about files and directories.

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

       strchr  strchr() is C-specific, see "index" in(1,8) 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(8,n) string(3,n) for the specified errno.  Identical to
               the string(3,n) form of the $!, see "$ERRNO" in(1,8) perlvar.

       strftime
               Convert date and time(1,2,n) 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(1,8) years since
               1900.  I.e., the year 1995 is 95; the year 2001 is 101.  Con-
               sult your system's "strftime()" manpage for details about these
               and the other arguments.

               If you want your code to be portable, your format ("fmt") argu-
               ment should use only the conversion specifiers defined by the
               ANSI C standard (C89, to play safe).  These are "aAbBcdHIjmMp-
               SUwWxXyYZ%".  But even then, the results of some of the conver-
               sion specifiers are non-portable.  For example, the specifiers
               "aAbBcpZ" change according to the locale(3,5,7) settings of the user,
               and both how to set(7,n,1 builtins) locales (the locale(3,5,7) names) and what output
               to expect are non-standard.  The specifier "c" changes accord-
               ing to the timezone settings of the user and the timezone com-
               putation 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(3,n) 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(1,8)
               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(1,8) perlfunc instead.

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

       strstr  This is identical to Perl's builtin "index()" function, see
               "index" in(1,8) perlfunc.

       strtod  String to double translation. Returns the parsed number and the
               number of characters in(1,8) the unparsed portion of the string.
               Truly POSIX-compliant systems set(7,n,1 builtins) $! ($ERRNO) to indicate a
               translation error(8,n), so clear(1,3x,3x clrtobot) $! before calling strtod.  However,
               non-POSIX systems may not check for overflow, and therefore
               will never set(7,n,1 builtins) $!.

               strtod should respect any POSIX setlocale() settings.

               To parse a string(3,n) $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(3,n) (($str eq '') || ($n_unparsed != 0) || !$!) {
                       die "Non-numeric input $str" . $! ? ": $!\n" : "\n";
                   }

               When called in(1,8) a scalar context strtod returns the parsed num-
               ber.

       strtok  strtok() is C-specific, use regular expressions instead, see
               perlre, or "split(1,n)" in(1,8) perlfunc.

       strtol  String to (long) integer translation.  Returns the parsed num-
               ber and the number of characters in(1,8) the unparsed portion of the
               string.  Truly POSIX-compliant systems set(7,n,1 builtins) $! ($ERRNO) to indi-
               cate a translation error(8,n), so clear(1,3x,3x clrtobot) $! before calling strtol.
               However, non-POSIX systems may not check for overflow, and
               therefore will never set(7,n,1 builtins) $!.

               strtol should respect any POSIX setlocale() settings.

               To parse a string(3,n) $str as a number in(1,8) 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(3,n) itself
               to determine the base: a leading "0x" or "0X" means hexadeci-
               mal; 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 num-
               ber.

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

                   if(3,n) (($str eq '') || ($n_unparsed != 0) || !$!) {
                       die "Non-numeric input $str" . $! ? ": $!\n" : "\n";
                   }

               When called in(1,8) a scalar context strtol returns the parsed num-
               ber.

       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 str-
               toul().  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(1,8) conjunction with the "strcoll()" function, see "str-
               coll".

               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(3,n) 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(1,8) perlfunc.

       tan     This is identical to the C function "tan()", returning the tan-
               gent 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(1,3) 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(1,2,n)    This is identical to Perl's builtin "time(1,2,n)()" function for
               returning the number of seconds since the epoch (whatever it is
               for the system), see "time(1,2,n)" in(1,8) perlfunc.

       times   The times() function returns elapsed realtime since some point
               in(1,8) the past (such as system startup), user and system times for
               this process, and user and system times used by child pro-
               cesses.  All times are returned in(1,8) clock(3,n) ticks.

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

               Note: Perl's builtin "times()" function returns four values,
               measured in(1,8) seconds.

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

       tmpnam  Returns a name for a temporary file.

                       $tmpfile = POSIX::tmpnam();

               For security reasons, which are probably detailed in(1,8) your sys-
               tem'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(1,8) 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(1,8) 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(1,2,n) 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 set-
               ting (and querying) the file(1,n) creation permission mask, see
               "umask" in(1,8) perlfunc.

       uname(1,2)   Get name of current operating system.

                       ($sysname, $nodename, $release, $version(1,3,5), $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(1,5), the $release might be
               the (major) release number of the operating system, the $ver-
               sion(1,3,5) might be the (minor) release number of the operating sys-
               tem, and the $machine might be a hardware identifier.  Maybe.

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

       unlink(1,2)  This is identical to Perl's builtin "unlink(1,2)()" function for
               removing files, see "unlink(1,2)" in(1,8) perlfunc.

       utime   This is identical to Perl's builtin "utime()" function for
               changing the time(1,2,n) stamps of files and directories, see "utime"
               in(1,8) perlfunc.

       vfprintf
               vfprintf() is C-specific, see "printf(1,3,1 builtins)" in(1,8) perlfunc instead.

       vprintf vprintf() is C-specific, see "printf(1,3,1 builtins)" in(1,8) perlfunc instead.

       vsprintf
               vsprintf() is C-specific, see "sprintf" in(1,8) perlfunc instead.

       wait    This is identical to Perl's builtin "wait()" function, see
               "wait" in(1,8) perlfunc.

       waitpid Wait for a child process to change state.  This is identical to
               Perl's builtin "waitpid()" function, see "waitpid" in(1,8) 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(1,2)   Write to a file.  This uses file(1,n) 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(1,8) perlfunc.

CLASSES
       POSIX::SigAction


       new     Creates a new "POSIX::SigAction" object which corresponds to
               the C "struct sigaction".  This object will be destroyed auto-
               matically 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 contains 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(7,n,1 builtins) 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(2,7) safely,
               use this accessor to set(7,n,1 builtins) the "safe" flag in(1,8) the "POSIX::SigAc-
               tion" object:

                       $sigaction->safe(1);

               You may also examine the "safe" flag on the output action
               object which is filled in(1,8) when given as the third parameter to
               "POSIX::sigaction()":

                       sigaction(SIGINT, $new_action, $old_action);
                       if(3,n) ($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;

               Create a set(7,n,1 builtins) with SIGUSR1.

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

       addset  Add a signal(2,7) to a SigSet object.

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

               Returns "undef" on failure.

       delset  Remove a signal(2,7) 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(3,n) it contains a specific sig-
               nal.

                       if(3,n)( $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(1,n) descriptor, and setattr() sets a
               file(1,n) descriptor's parameters to match Termios' contents.

                       $termios = POSIX::Termios->new;

       getattr Get terminal control attributes.

               Obtain the attributes for stdin.

                       $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.

       setcc   Set a value in(1,8) 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

       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_VDIS-
               ABLE

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 EAL-
               READY 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 ENETUN-
               REACH ENFILE ENOBUFS ENODEV ENOENT ENOEXEC ENOLCK ENOMEM ENO-
               PROTOOPT ENOSPC ENOSYS ENOTBLK ENOTCONN ENOTDIR ENOTEMPTY ENOT-
               SOCK ENOTTY ENXIO EOPNOTSUPP EPERM EPFNOSUPPORT EPIPE EPROCLIM
               EPROTONOSUPPORT EPROTOTYPE ERANGE EREMOTE ERESTART EROFS ESHUT-
               DOWN 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 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

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(3,n) the child process
                               exited normally ("exit(3,n,1 builtins)()" or by falling off the
                               end of "main()")

               WEXITSTATUS     WEXITSTATUS($?) returns the normal exit(3,n,1 builtins) status
                               of the child process (only meaningful if(3,n) WIFEX-
                               ITED($?) is true)

               WIFSIGNALED     WIFSIGNALED($?) returns true if(3,n) the child
                               process terminated because of a signal(2,7)

               WTERMSIG        WTERMSIG($?) returns the signal(2,7) the child
                               process terminated for (only meaningful if(3,n)
                               WIFSIGNALED($?) is true)

               WIFSTOPPED      WIFSTOPPED($?) returns true if(3,n) the child
                               process is currently stopped (can happen only
                               if(3,n) you specified the WUNTRACED flag to wait-
                               pid())

               WSTOPSIG        WSTOPSIG($?) returns the signal(2,7) the child
                               process was stopped for (only meaningful if(3,n)
                               WIFSTOPPED($?) is true)



perl v5.8.5                       2001-09-21                          POSIX(3)

References for this manual (incoming links)