18.104.22.168 For trunc(x), the value of trunc(x) is such that if x is positive or zero then 0<=x-trunc(x)<1; otherwise -1<x-trunc(x)<=0. It is an error if such a value does not exist.
In other words, it is an error to use the trunc function to convert a value of real type into a value of integral type, if the real value is outside the range of integral values supported by Irie Pascal. For example
is an error.
This error is never reported.