Kaveh R. Ghazi wrote:- > I.e. the last compare of "u < (u1-u2)" doesn't warn. Is this a bug or > feature? Doesn't (u1-u2) become an integer? Please explain. :-) No, the type of the result is the type of the operands for most (all?) operators in C. The others convert the unsigned operand to signed, and therefore the result of the subtraction is signed. Neil.