Function nanocbor_fmt_double

pub unsafe extern "C" fn nanocbor_fmt_double(
    enc: *mut nanocbor_encoder_t,
    num: f64,
) -> c_int

@brief Write a double floating point value into the encoder buffer

@param[in] enc Encoder context @param[in] num Floating point to encode

@return Number of bytes written @return Negative on error