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BCDE NEYASOV JHTHORSEN SYP BIFFEN

136 PAUSE users
117 non-PAUSE users.

Gurusamy Sarathy

NAME

integer - Perl pragma to compute arithmetic in integer instead of double

SYNOPSIS

    use integer;
    $x = 10/3;
    # $x is now 3, not 3.33333333333333333

DESCRIPTION

This tells the compiler to use integer operations from here to the end of the enclosing BLOCK. On many machines, this doesn't matter a great deal for most computations, but on those without floating point hardware, it can make a big difference.

Note that this affects the operations, not the numbers. If you run this code

    use integer;
    $x = 1.5;
    $y = $x + 1;
    $z = -1.5;

you'll be left with $x == 1.5, $y == 2 and $z == -1. The $z case happens because unary - counts as an operation.

Native integer arithmetic (as provided by your C compiler) is used. This means that Perl's own semantics for arithmetic operations may not be preserved. One common source of trouble is the modulus of negative numbers, which Perl does one way, but your hardware may do another.

  % perl -le 'print (4 % -3)'
  -2
  % perl -Minteger -le 'print (4 % -3)'
  1

See "Pragmatic Modules" in perlmod.