From GridLAB-D Wiki
Integers requiring 32 bits are stored in an int32 built-in data type. An int32 value can represent values between − 2,147,483,648 to 2,147,483,647.
An attempt to store a value outside that range is unpredictable.
GLM
To declare an int32 value in a class use the syntax
class my_class { int32 my_string; }
To define an integer value in an object use the syntax
object my_class { my_integer 123; }
where "value" is a integer within the range of a 32 bit integer.