Warning flags for unsigned operations (unsafe)

[Thomas R. Truscott]

 > I couldn't find out if gcc had a 
 > warning flag for unsigned operation. For example, even the linear 
 > interpolation on [a,b] can be tricky to code:
 > 
 >  c = a + t * (b - a);  //unsafe

Not for this situation.  I think a warning would be appropriate
when an unsigned quantity involving subtraction
is widened or converted to double.

 >   Your code has a design flaw and is not valid.  

Uh, that misses the whole point of warning messages, doesn't it?

Tom Truscott