Portability of binary serialization of double/float type in C++

Question

The C++ standard does not discuss the underlying layout of float and double types, only the range of values they should represent. (This is also true for signed types, is i

Answer 1

Just write the binary IEEE754 representation to disk, and document this as your storage format (along with is endianness). Then it's up to the implementation to convert this to its internal representation if necessary.