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bigint(3)	       Perl Programmers	Reference Guide		     bigint(3)

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.

       t or trace
	 This enables a	trace mode and is primarily for	debugging bigint or
	 Math::BigInt.

       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. 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,	then
       Math::BigInt::Bar, and when this	also fails, revert to
       Math::BigInt::Calc:

	       use bigint lib => 'Foo,Math::BigInt::Bar';

       Using "lib" warns if none of the	specified libraries can	be found and
       Math::BigInt 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, or Math::BigInt::Lite.
       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), " ", $y,"\n";	       # prints	10 10

	       $x = 9; $y = $x;
	       print $x->binc(1), " ", $y,"\n";	       # prints	10 10

	       $x = 9; $y = $x;
	       print $x->bmul(2), " ", $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->binf(). Useful because Perl	does
	 not always handle bareword "inf" properly.

       NaN()
	 A shortcut to return Math::BigInt->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). 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)'

       upgrade()
	 Return	the class that numbers are upgraded to,	is in fact returning
	 $Math::BigInt::upgrade.

       in_effect()
		 use bigint;

		 print "in effect\n" if	bigint::in_effect;	 # true
		 {
		   no bigint;
		   print "in effect\n" if bigint::in_effect;	 # 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 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"	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()/oct()
	 "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 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      (for speed, and only if it is loadable)
	       Math::BigInt

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)'
	       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)'
	       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, Math::BigFloat, Math::BigRat and Math::Big	as well	as
       Math::BigInt::FastCalc, Math::BigInt::Pari and Math::BigInt::GMP.

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

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

perl v5.32.0			  2020-06-14			     bigint(3)

NAME | SYNOPSIS | DESCRIPTION | CAVEATS | MODULES USED | EXAMPLES | BUGS | SUPPORT | LICENSE | SEE ALSO | AUTHORS

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