12.6.7 Rounding function

Unsafe Operation: $flround fl

Return the closest integral flonum to the operand, rounding to even when fl represents a number halfway between two integers.

Unsafe Operation: $flfloor fl

Return the largest integral flonum not larger than the operand.

Unsafe Operation: $flceiling fl

Return the smallest integral flonum not larger than the operand.

Unsafe Operation: $fltruncate fl

Return the integral flonum closest to the operand whose absolute value is not larger than the absolute value of the operand itself.