opCmp with double values

[kerdemdemir via Digitalmars-d-learn]

In documentation and forums I found some example for overloading 
opCmp for int values. But I couldn't see any examples for double 
values.

That is what I come up with my own:
struct AdjustableVal ( T = double )
{
        this ( T initVal )
        {
                curVal = initVal;
                initialVal = initVal;
        }
        
        
    int opCmp( T rhs ) const {
        auto diff = curVal - rhs;
        if (  fabs(diff) < 0.00000001 )
            return 0;
        else if ( diff < 0 )
            return -1;
        else
            return 1;
     }

        T curVal;
        T initialVal;
}

Do you guys see any problem with it or any suggestions?
Secondly if the value type(T) does not have "-" operator, is it 
possible to still get my code compiled somehow with static_if?


Erdem