Glen wrote:
I guess I don't understand the whole concept now. T* -> void* sounds like "narrowing", since it loses information. int -> long never loses information, so "widening" makes sense to me. What is the criterion?
This is why I like C++'s choice of base and derived, there's never any confusion. You have the concepts of narrowing and widening correct but backwards. You narrow a type to a more specific derived type and widen one to a more general base type.
That is why we should always use "covariant" and "contravariant" conversions, instead of (the proper but potentially confusing - if the reader is in "number of bits" mode) "narrowing" and "widening." This confusion leads to a shock when encountering the pointer-to-pointer conversions in C++. One has to understand the oscillation between covariance and contravariance when the indirections are traversed. I will personally spam the next writer using "narrowing" or "widening" ;-) /David