Portable serialisation of IEEE754 floating-point values

Question

I\'ve recently been working on a system that needs to store and load large quantities of data, including single-precision floating-point values. I decided to standardise on

Answer 1

Much simpler, and depending on the same assumption as yours (which is that float and integer types have the same byte order, and is almost universally valid -- realistically you'll never encounter a system where it isn't true):

#include 

float htonf(float val) {
    uint32_t rep;
    memcpy(&rep, &val, sizeof rep);
    rep = htonl(rep);
    memcpy(&val, &rep, sizeof rep);
    return val;
}

Any reasonably good compiler will optimize away the two memcpy calls; they are present to defeat over-eager strict aliasing optimizations, so this ends up being as efficient as htonl plus the overhead of a single function call.