On 7 June 2012 18:52, Jonathan Wakely wrote: > On 7 June 2012 18:09, Arthur Schwarz wrote: >> >> >> I am using g++ 4.5.3 as my compiler and NetBeans 7.1.2 as my IDE. >> >> What I wnat to do is to overload operators using all selected types. What I get >> are error messages indicating that the usage is ambiquous. I understaad that >> the runtime usage may be ambiguous using literal values. > > Literals are not run-time values, they are compile-time values, a call > using a literal must be resolved at compile-time like any other call. > >> I don't understand why >> a typed variable would cause ambiguity. And I would like to know how to code >> around the issue. The issue (to me) is that char can be widened to long, and >> unsigned char can be widened to unsigned long, but how do I take care of issues char can be promoted to int, and unsigned char can be promoted to unsigned int. >> between unsigned (char or long) and signed (char or long) since their ranges >> are different. > > A long can be converted to any of the types you have overloaded the > function for, there is no "hierarchy" of types that a long would > prefer to convert to. Actually that's not accurate, there is a conversion rank for integers, but for the types you've used long doesn't "prefer" to convert to any of them. > You should overload the function for all types you need it for or > explicitly convert the argument to one of the types you have > overloaded the function for.
