Availability:Arithmetic function (see is/2) 
[ISO]+IntExpr1 // +IntExpr2Integer division, defined as Result is rnd_I(Expr1/Expr2) 
. The function rnd_I is the default rounding used by the C 
compiler and available through the Prolog flag
integer_rounding_function. 
In the C99 standard, C-rounding is defined as towards_zero.126Future 
versions might guarantee rounding towards zero.