The tips of the day says that Const is short for constant. The function Const can only be set to a variable. It cannot be called or used with an if statement. It was removed in 1.4.5. I'm still not sure what the two parameters represent and how to use them though.
The reason I am mentioning this is because I suspect that function has to do with the system variable disablesysconstreset which to this day nobody knows what it does. I went through hell trying to figure out what constantly resets in a level with no luck. Not even the Const parameter in the function FXcreate. Finding out those two parameters in the Const function will give me a better idea of how it can be used or something to rule out.