CONTENTS

• NAME
• SYNOPSIS
• DESCRIPTION
  • use integer vs. use bigint
  • Options
  • Math Library
  • Internal Format
  • Sign
  • Method calls
  • Methods
• CAVEATS
• MODULES USED
• EXAMPLES
• BUGS
• SUPPORT
• LICENSE
• SEE ALSO
• AUTHORS

#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) + 0'
2
# perl -Mbigint -wle 'print exp(1)'
2
# perl -Minteger -wle 'print exp(1)'
2.71828182845905
# perl -Minteger -wle 'print exp(1) + 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'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'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.

#