# phpman > man > bigint(3perl)

## NAME
    bigint - Transparent BigInteger support for Perl

## SYNOPSIS
      use bigint;

      $x = 2 + 4.5,"\n";                    # BigInt 6
      print 2 ** 512,"\n";                  # really is what you think it is
      print inf + 42,"\n";                  # inf
      print NaN * 7,"\n";                   # NaN
      print hex("0x1234567890123490"),"\n"; # Perl v5.10.0 or later

      {
        no bigint;
        print 2 ** 256,"\n";                # a normal Perl scalar now
      }

      # Import into current package:
      use bigint qw/hex oct/;
      print hex("0x1234567890123490"),"\n";
      print oct("01234567890123490"),"\n";

## DESCRIPTION
    All operators (including basic math operations) except the range operator ".." are overloaded.
    Integer constants are created as proper BigInts.

    Floating point constants are truncated to integer. All parts and results of expressions are also
    truncated.

    Unlike integer, this pragma creates integer constants that are only limited in their size by the
    available memory and CPU time.

  use integer vs. use bigint
    There is one small difference between "use integer" and "use bigint": the former will not affect
    assignments to variables and the return value of some functions. "bigint" truncates these
    results to integer too:

            # perl -Minteger -wle 'print 3.2'
            3.2
            # perl -Minteger -wle 'print 3.2 + 0'
            3
            # perl -Mbigint -wle 'print 3.2'
            3
            # perl -Mbigint -wle 'print 3.2 + 0'
            3

            # perl -Mbigint -wle 'print [exp(1)](https://www.chedong.com/phpMan.php/man/exp/1/markdown) + 0'
            2
            # perl -Mbigint -wle 'print [exp(1)](https://www.chedong.com/phpMan.php/man/exp/1/markdown)'
            2
            # perl -Minteger -wle 'print [exp(1)](https://www.chedong.com/phpMan.php/man/exp/1/markdown)'
            2.71828182845905
            # perl -Minteger -wle 'print [exp(1)](https://www.chedong.com/phpMan.php/man/exp/1/markdown) + 0'
            2

    In practice this makes seldom a difference as parts and results of expressions will be truncated
    anyway, but this can, for instance, affect the return value of subroutines:

        sub three_integer { use integer; return 3.2; }
        sub three_bigint { use bigint; return 3.2; }

        print three_integer(), " ", three_bigint(),"\n";    # prints "3.2 3"

### Options
    bigint recognizes some options that can be passed while loading it via use. The options can
    (currently) be either a single letter form, or the long form. The following options exist:

    a or accuracy
      This sets the accuracy for all math operations. The argument must be greater than or equal to
      zero. See [Math::BigInt](https://www.chedong.com/phpMan.php/perldoc/Math%3A%3ABigInt/markdown)'s bround() function for details.

              perl -Mbigint=a,2 -le 'print 12345+1'

      Note that setting precision and accuracy at the same time is not possible.

    p or precision
      This sets the precision for all math operations. The argument can be any integer. Negative
      values mean a fixed number of digits after the dot, and are <B>ignored</B> since all
      operations happen in integer space. A positive value rounds to this digit left from the dot. 0
      or 1 mean round to integer and are ignore like negative values.

      See [Math::BigInt](https://www.chedong.com/phpMan.php/perldoc/Math%3A%3ABigInt/markdown)'s bfround() function for details.

              perl -Mbignum=p,5 -le 'print 123456789+123'

      Note that setting precision and accuracy at the same time is not possible.

    t or trace
      This enables a trace mode and is primarily for debugging bigint or [Math::BigInt](https://www.chedong.com/phpMan.php/perldoc/Math%3A%3ABigInt/markdown).

    hex
      Override the built-in hex() method with a version that can handle big integers. This overrides
      it by exporting it to the current package. Under Perl v5.10.0 and higher, this is not so
      necessary, as hex() is lexically overridden in the current scope whenever the bigint pragma is
      active.

    oct
      Override the built-in oct() method with a version that can handle big integers. This overrides
      it by exporting it to the current package. Under Perl v5.10.0 and higher, this is not so
      necessary, as oct() is lexically overridden in the current scope whenever the bigint pragma is
      active.

    l, lib, try or only
      Load a different math lib, see "Math Library".

              perl -Mbigint=lib,GMP -e 'print 2 ** 512'
              perl -Mbigint=try,GMP -e 'print 2 ** 512'
              perl -Mbigint=only,GMP -e 'print 2 ** 512'

      Currently there is no way to specify more than one library on the command line. This means the
      following does not work:

              perl -Mbignum=l,GMP,Pari -e 'print 2 ** 512'

      This will be hopefully fixed soon ;)

    v or version
      This prints out the name and version of all modules used and then exits.

              perl -Mbigint=v

### Math Library
    Math with the numbers is done (by default) by a module called [Math::BigInt::Calc](https://www.chedong.com/phpMan.php/perldoc/Math%3A%3ABigInt%3A%3ACalc/markdown). This is
    equivalent to saying:

            use bigint lib => 'Calc';

    You can change this by using:

            use bignum lib => 'GMP';

    The following would first try to find [Math::BigInt::Foo](https://www.chedong.com/phpMan.php/perldoc/Math%3A%3ABigInt%3A%3AFoo/markdown), then [Math::BigInt::Bar](https://www.chedong.com/phpMan.php/perldoc/Math%3A%3ABigInt%3A%3ABar/markdown), and when this
    also fails, revert to [Math::BigInt::Calc](https://www.chedong.com/phpMan.php/perldoc/Math%3A%3ABigInt%3A%3ACalc/markdown):

            use bigint lib => 'Foo,[Math::BigInt::Bar](https://www.chedong.com/phpMan.php/perldoc/Math%3A%3ABigInt%3A%3ABar/markdown)';

    Using "lib" warns if none of the specified libraries can be found and [Math::BigInt](https://www.chedong.com/phpMan.php/perldoc/Math%3A%3ABigInt/markdown) did fall back
    to one of the default libraries. To suppress this warning, use "try" instead:

            use bignum try => 'GMP';

    If you want the code to die instead of falling back, use "only" instead:

            use bignum only => 'GMP';

    Please see respective module documentation for further details.

### Internal Format
    The numbers are stored as objects, and their internals might change at anytime, especially
    between math operations. The objects also might belong to different classes, like [Math::BigInt](https://www.chedong.com/phpMan.php/perldoc/Math%3A%3ABigInt/markdown),
    or [Math::BigInt::Lite](https://www.chedong.com/phpMan.php/perldoc/Math%3A%3ABigInt%3A%3ALite/markdown). Mixing them together, even with normal scalars is not extraordinary, but
    normal and expected.

    You should not depend on the internal format, all accesses must go through accessor methods.
    E.g. looking at $x->{sign} is not a good idea since there is no guaranty that the object in
    question has such a hash key, nor is a hash underneath at all.

### Sign
    The sign is either '+', '-', 'NaN', '+inf' or '-inf'. You can access it with the sign() method.

    A sign of 'NaN' is used to represent the result when input arguments are not numbers or as a
    result of 0/0. '+inf' and '-inf' represent plus respectively minus infinity. You will get '+inf'
    when dividing a positive number by 0, and '-inf' when dividing any negative number by 0.

### Method calls
    Since all numbers are now objects, you can use all functions that are part of the BigInt API.
    You can only use the bxxx() notation, and not the fxxx() notation, though.

    But a warning is in order. When using the following to make a copy of a number, only a shallow
    copy will be made.

            $x = 9; $y = $x;
            $x = $y = 7;

    Using the copy or the original with overloaded math is okay, e.g. the following work:

            $x = 9; $y = $x;
            print $x + 1, " ", $y,"\n";     # prints 10 9

    but calling any method that modifies the number directly will result in both the original and
    the copy being destroyed:

            $x = 9; $y = $x;
            print $x->[badd(1)](https://www.chedong.com/phpMan.php/man/badd/1/markdown), " ", $y,"\n";        # prints 10 10

            $x = 9; $y = $x;
            print $x->[binc(1)](https://www.chedong.com/phpMan.php/man/binc/1/markdown), " ", $y,"\n";        # prints 10 10

            $x = 9; $y = $x;
            print $x->[bmul(2)](https://www.chedong.com/phpMan.php/man/bmul/2/markdown), " ", $y,"\n";        # prints 18 18

    Using methods that do not modify, but test that the contents works:

            $x = 9; $y = $x;
            $z = 9 if $x->is_zero();                # works fine

    See the documentation about the copy constructor and "=" in overload, as well as the
    documentation in BigInt for further details.

### Methods
### inf
      A shortcut to return [Math::BigInt](https://www.chedong.com/phpMan.php/perldoc/Math%3A%3ABigInt/markdown)->binf(). Useful because Perl does not always handle bareword
      "inf" properly.

    NaN()
      A shortcut to return [Math::BigInt](https://www.chedong.com/phpMan.php/perldoc/Math%3A%3ABigInt/markdown)->bnan(). Useful because Perl does not always handle bareword
      "NaN" properly.

    e
              # perl -Mbigint=e -wle 'print e'

      Returns Euler's number "e", aka [exp(1)](https://www.chedong.com/phpMan.php/man/exp/1/markdown). Note that under bigint, this is truncated to an
      integer, and hence simple '2'.

    PI
              # perl -Mbigint=PI -wle 'print PI'

      Returns PI. Note that under bigint, this is truncated to an integer, and hence simple '3'.

### bexp
              bexp($power,$accuracy);

      Returns Euler's number "e" raised to the appropriate power, to the wanted accuracy.

      Note that under bigint, the result is truncated to an integer.

      Example:

              # perl -Mbigint=bexp -wle 'print bexp(1,80)'

### bpi
              bpi($accuracy);

      Returns PI to the wanted accuracy. Note that under bigint, this is truncated to an integer,
      and hence simple '3'.

      Example:

              # perl -Mbigint=bpi -wle 'print [bpi(80)](https://www.chedong.com/phpMan.php/man/bpi/80/markdown)'

### upgrade
      Return the class that numbers are upgraded to, is in fact returning $[Math::BigInt::upgrade](https://www.chedong.com/phpMan.php/perldoc/Math%3A%3ABigInt%3A%3Aupgrade/markdown).

### in_effect
              use bigint;

              print "in effect\n" if [bigint::in_effect](https://www.chedong.com/phpMan.php/perldoc/bigint%3A%3Aineffect/markdown);       # true
              {
                no bigint;
                print "in effect\n" if [bigint::in_effect](https://www.chedong.com/phpMan.php/perldoc/bigint%3A%3Aineffect/markdown);     # false
              }

      Returns true or false if "bigint" is in effect in the current scope.

      This method only works on Perl v5.9.4 or later.

## CAVEATS
    Operator vs literal overloading
      "bigint" works by overloading handling of integer and floating point literals, converting them
      to [Math::BigInt](https://www.chedong.com/phpMan.php/perldoc/Math%3A%3ABigInt/markdown) objects.

      This means that arithmetic involving only string values or string literals will be performed
      using Perl's built-in operators.

      For example:

          use bignum;
          my $x = "900000000000000009";
          my $y = "900000000000000007";
          print $x - $y;

      will output 0 on default 32-bit builds, since "bigint" never sees the string literals. To
      ensure the expression is all treated as "[Math::BigInt](https://www.chedong.com/phpMan.php/perldoc/Math%3A%3ABigInt/markdown)" objects, use a literal number in the
      expression:

          print +(0+$x) - $y;

    ranges
      Perl does not allow overloading of ranges, so you can neither safely use ranges with bigint
      endpoints, nor is the iterator variable a bigint.

              use 5.010;
              for my $i (12..13) {
                for my $j (20..21) {
                  say $i ** $j;  # produces a floating-point number,
                                 # not a big integer
                }
              }

### in_effect
      This method only works on Perl v5.9.4 or later.

### hex
      "bigint" overrides these routines with versions that can also handle big integer values. Under
      Perl prior to version v5.9.4, however, this will not happen unless you specifically ask for it
      with the two import tags "hex" and "oct" - and then it will be global and cannot be disabled
      inside a scope with "no bigint":

              use bigint qw/hex oct/;

              print hex("0x1234567890123456");
              {
                      no bigint;
                      print hex("0x1234567890123456");
              }

      The second call to hex() will warn about a non-portable constant.

      Compare this to:

              use bigint;

              # will warn only under Perl older than v5.9.4
              print hex("0x1234567890123456");

## MODULES USED
    "bigint" is just a thin wrapper around various modules of the [Math::BigInt](https://www.chedong.com/phpMan.php/perldoc/Math%3A%3ABigInt/markdown) family. Think of it
    as the head of the family, who runs the shop, and orders the others to do the work.

    The following modules are currently used by bigint:

            [Math::BigInt::Lite](https://www.chedong.com/phpMan.php/perldoc/Math%3A%3ABigInt%3A%3ALite/markdown)      (for speed, and only if it is loadable)
            [Math::BigInt](https://www.chedong.com/phpMan.php/perldoc/Math%3A%3ABigInt/markdown)

## EXAMPLES
    Some cool command line examples to impress the Python crowd ;) You might want to compare them to
    the results under -Mbignum or -Mbigrat:

            perl -Mbigint -le 'print [sqrt(33)](https://www.chedong.com/phpMan.php/man/sqrt/33/markdown)'
            perl -Mbigint -le 'print 2*255'
            perl -Mbigint -le 'print 4.5+2*255'
            perl -Mbigint -le 'print 3/7 + 5/7 + 8/3'
            perl -Mbigint -le 'print 123->is_odd()'
            perl -Mbigint -le 'print [log(2)](https://www.chedong.com/phpMan.php/man/log/2/markdown)'
            perl -Mbigint -le 'print 2 ** 0.5'
            perl -Mbigint=a,65 -le 'print 2 ** 0.2'
            perl -Mbignum=a,65,l,GMP -le 'print 7 ** 7777'

## BUGS
    For information about bugs and how to report them, see the BUGS section in the documentation
    available with the perldoc command.

        perldoc bignum

## SUPPORT
    You can find documentation for this module with the perldoc command.

        perldoc bigint

    For more information, see the SUPPORT section in the documentation available with the perldoc
    command.

        perldoc bignum

## LICENSE
    This program is free software; you may redistribute it and/or modify it under the same terms as
    Perl itself.

## SEE ALSO
    bignum and bigrat.

    [Math::BigInt](https://www.chedong.com/phpMan.php/perldoc/Math%3A%3ABigInt/markdown), [Math::BigFloat](https://www.chedong.com/phpMan.php/perldoc/Math%3A%3ABigFloat/markdown), [Math::BigRat](https://www.chedong.com/phpMan.php/perldoc/Math%3A%3ABigRat/markdown) and [Math::Big](https://www.chedong.com/phpMan.php/perldoc/Math%3A%3ABig/markdown) as well as [Math::BigInt::FastCalc](https://www.chedong.com/phpMan.php/perldoc/Math%3A%3ABigInt%3A%3AFastCalc/markdown),
    [Math::BigInt::Pari](https://www.chedong.com/phpMan.php/perldoc/Math%3A%3ABigInt%3A%3APari/markdown) and [Math::BigInt::GMP](https://www.chedong.com/phpMan.php/perldoc/Math%3A%3ABigInt%3A%3AGMP/markdown).

## AUTHORS
    *   (C) by Tels <<http://bloodgate.com/>> in early 2002 - 2007.

    *   Maintained by Peter John Acklam <<pjacklam@gmail.com><gt>, 2014-.