Re: [boost] [1.35][functional] gcc-4.2:dereferencing type-punned pointer will break strict-aliasing rules

On Friday 18 April 2008, Giovanni Piero Deretta wrote:

     inline std::size_t float_hash_impl(float v)      {             std::size_t seed;             std::memcpy(&x, &v, sizeof(x));             return seed;      }

should work and should produce optimal code, at least with a recent gcc.

Wouldn't casting using union be safe and efficient in all cases? Something like: inline std::size_t float_hash_impl(float v) { union { float v; std::size_t seed; } u; u.v = v; return u.seed; } Teemu