Is static_cast(-1) the right way to generate all-one-bits data without numeric_limits?

Question

I\'m writing C++ code in an environment in which I don\'t have access to the C++ standard library, specifically not to std::numeric_limits. Suppose I want to implem

Answer 1

Use the bitwise NOT operator ~ on 0.

T allOnes = ~(T)0;

A static_cast(-1) assumes two's complement, which is not portable. If you are only concerned about unsigned types, hvd's answer is the way to go.

Working example: https://ideone.com/iV28u0