Official Description
6.6.6.3 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.
Simplified Description
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
trunc(1.0e16)is an error.
Error Handling
This error is never reported.