int
See the current Perl documentation for int.
Here is our local, out-dated (pre-5.6) version:

int - get the integer portion of a number

int EXPR
int

Returns the integer portion of
EXPR. If
EXPR is omitted, uses
$_
. You should not use this for rounding, because it truncates towards 0
, and because machine representations of floating point numbers can
sometimes produce counterintuitive results. Usually sprintf() or printf(), or the POSIX::floor
or POSIX::ceil
functions, would serve you better.