Nope! Same. BTW the memcpy is always optimized out, so you might as well; then it's totes portable, C or C++. You can always build up an object (int, float, struct) from char values. Technically they are supposed to have come from another value of the same type, but the compiler can't really tell where the bytes came from, so has to assume they must have come from there.

C does have a thing where a void pointer can be copied into any other pointer, without a cast, and operations with the typed pointer are OK. Technically, the pointer value is supposed to have been copied to the void pointer from the same type, but realloc has to work. Note, realloc does give you alignment guarantees you don't get from pointers to random things.

Nothing else is portable. Unions, other pointer casting, all is UB unless your compiler extends the definition. So, Gcc has an extension to make unions, used in a certain way, well-defined. Probably Clang copies that. You would have to look up exactly what. But the memcpy hack works in all compilers. You won't use it often enough for the extra verbosity to be a problem.

In C you're free to get the address of the float (presuming it's not in a register) and cast that address to a pointer to an array of char, which doesn't copy anything, just re-decrees, from that point on, to the code generator of the compiler what assembly code is generated.