Thats wrong. Double is actually 8 byte in size (var is 4 byte) and can contain a MUCH bigger numbers (or much smaller, or more precise).
Its an array of vars, nothing else
In Zorro lite-C, var is 8 bytes and is indeed a synonym for double. This is different to Gamestudio lite-C, where var is 4 bytes and a synonym for 22.10 fixed. "var" is just the standard variable type used for the specific application.
