integer - Perl pragma to compute arithmetic in integer instead of double
use integer;
$x = 10/3;
# $x is now 3, not 3.33333333333333333
This tells the compiler that it's okay 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.
See Pragmatic Modules.